Sure wish I had this when I was a mechanic's instructor. This is one of the most concise, well conceived and presented little video "vignettes" on this subject I have ever seen. WELL DONE SIR! Thank YOU!
The best electronic teacher I never had in my life ! Thank you so much to speak so slowly for foreigners ( like me). Everything is so clear. Thierry ( from France)
I have been teaching electronics at a local university, and will recommend my students to watch this video even though we don't go into power electronics. This is an excellent video describing the basics of a CDI system. There is supposed to be a signal conditioning circuit in the pulse rotator path that terminates at the SCR gate; its main function is to clean/filter the spikes from the triggering mechanism. All in all your explanation is very clear, and concise. Thanks for uploading the video.
I would like to add a note here, because it seems some people having trouble understanding it. Not all cdi's have this excitor coil, some old cdi's have that. Most of them nowdays have an inverter build in. These kinds of cdi's gets their power directly from the battery.
Highly invaluable video, I saved a lot of time and money making my own CDI circuit from basically exactly this schematic for a 125cc dirt bike. 100ohm resistor, 1n4007 diodes, 1uf 250v cap and a BT169D thyristor.
Hi good work frank this project, I need to make this CDI of my dirt bike he is a suzuki rm 125 92 you know its work on my motorcycle? send me a e-mail please i realy need this project help me please, sende from: ph_monteiro2005@hotmail.com
HI All American Five today I opened an original dirt bike CDI, I can see to have a 250v orange capacitor, I am from Brazil, but I did not think to buy this cdi here and when I thought it was very expensive 450 500 $ How Do I understand enough of electronics to make my own cdi
Excellent description. Just what I was looking for. It's difficult for me to comprehend how my new CDI distributor on my 1974 Ford 302 V-8 manages to "trigger" with the components I see withing the distributor cap. Not that it makes an difference, but mine is a marine application. Thank you very much for the description.
an excellent explanation. thank you. I had no idead what vehicle ignition was until yesterday, but watching this video, I can totally comprehend what vehicle ignition is and how CDI works.
I have been trying to learn and diagnose a small engine with no spark. these type videos are great ! Im almost amazed at the effort people put into these videos and the value that we all can get out of them. Im no engine or electronics expert but i know enough to fix some things and other times royally ruin things. I might be totally wrong but it doesn't make sense to me that the ignition's primary coil is grounded directly. I figured it would get the solid ground thru the gate(SCR/transistor or whatever it is)
Great explanation ! I envy your ability to simplify this to the point where anyone could understand... even after watching your video, I couldn't explain it so clearly. I get so caught up on details... I'd go off on a rant about timing advance curves, 2 cycle vs 4 cycle, coil fed vs battery fed ... and I'd walk frustrated and with the other person more confused than when I started.
Ha, brilliant! My mechanic just said my boat needed a trigger today, so when I found your video, it explained EXACTLY the info I wanted to understand. Kudos to you sir!!!!
Thanks Rick for uploading this video,, little bit of insight for others. Pulse coil is the one which would trigger when piston comes to top dead center in motor bikes. IN four stroke engine, u have intake(getting GA), compression(compress the GAS), spark(spark the compressed gas) and exhaust as four events, u want to spark the engine at the top of compression stroke, pulse coil will provide pulse exactly at that stage.. In Cars Transistor is used to pulse the coil ground and power is steady
Thanks Daniel, I've been busy working on a 50,000 Watt transmitter. Both three-phase circuit breakers failed. The station was off the air since Wednesday afternoon, got the parts in today and she's back on the air. Glad the video was helpful. Rick
I put a CDI system in a Ford 4 cylinder Cortina many years ago and straight away noticed more power and better idling , except one night i noticed that the engine was idling roughly when I opened the hood it looked like a Xmas tree, sparks leaking from all over the spark plug leads .The higher induced voltages must of been to much for the leads , the simple solution then was to buy HV insulating sleeve and install the leads inside.
I normally watch your radio videos. My 1984 Honda "Big Red" stopped running. What a pleasant surprise to find YOUR video covering this! Great job as always. The Big Red is running now, by the way. Thanks again my friend!
Rich, Great information. This helps to understand various components. Now it also helps to see how the function in a radio or any other device. 73, Mike
Interesting. I was trying to figure out an Amazon review for a small engine accessory coil to provide 12 volts for gas engine bicycle lighting. This reviewer said that just adding the aftermarket coil (approx 180 degrees from the ignition charge coil) kept his engine from running more than 3,000 rpm. We used to do this exact trick with old Ducati and other euro "scrambler" dirt bikes that only had one magneto coil so we could get some lighting, and it was never a problem. Of course, those were the days of separate spark coils with contact breaker points (and incandescent lights that didn't care about the non-rectified AC pulse from the lighting coil), but still, I'm having a hard time understanding how adding another coil would possibly have any affect on the CDI system. The aftermarket coil is grounded to the engine and has one power lead coming from the other end of the coil, so both the ignition coil and the aftermarket lighting coil share the engine block as a ground - but that shouldn't be an issue... should it? Strange, eh?
GREAT description of how a CDI works, easy to understand. I need to build a CDI for a motorcycle engine that uses two trigger coils. One at 10 BDTC and another at 35 BTDC. I assume I'd duplicate the SCR to the trigger circuit. But how would it "switch" to the 35 BTDC trigger as the engine speeds up? I need the advance to occur before 2,500 rpm.
CDI isn't the "black box" you thought it was. An SCR, v. a transistor, is used to ensure a more complete discharge of the capacitor to induce more voltage in the secondary coil. An SCR conducts until a reverse voltage is applied to its gate or, in this case, the capacitor fully discharges.
Yes without the diode operating the ignition stop switch would kill the engine and stop the ignition from firing. Without the diode there would be twice as much current through the exciter coil which also means twice as much heat. The designer of the circuit has determine that there would be no damage to the exciter coil by adding a diode, and ignition stop switch still stops the ignition from firing.
No pulse coil in car's. I would guess this is an ignition system for a lawnmower but this is just a guess. Modern automotive (and motorcycle) ignition systems are slightly more complex and use a crank sensor and a camshaft sensor (faster start times) and do not generate their own power from a magneto as this demo shows. All the other concepts are the same. Very nice demo Rick.
the best explanation and workind of this circuit i have seen. my question on this is a ac cdi what is difference between dc/ac operation other tha alternating and direct?
Silicon Control Rectifier SCR Basic AC Circuit ruclips.net/video/45H4J_S52Y4/видео.html Silicon Control Rectifier SCR Basic DC Circuit ruclips.net/video/ImyTwZGZ-Ls/видео.html
yes modern car have Cam sensor(provides which cylinder is top), and crank sensor(provides whether cylinder is approaching top dead or not) is fed to ECM/PCM, then PCM will send pulse signal to ICM(igniter) which will momentarily supply ground(using transistor switch on / off) to the ground side of the coil, note positive is 12 volt connected all the time, this makes a spark..
Hello sir. Thank you for helping us along understand some of the mysteries of modern electrical automotive systems. I have a question if you don't mind. In a typical application of the CDI, how many "charge cycles' would you say is necessary to create enough charge in the capacitor? I ask because I really wonder how charging the capacitor is accomplished on say a single cylinder 2 stroke motorcycle engine. If a 2 stroke fires every single revolution of the crank shaft, and the CDI magnet system is tied to its rotation, then you pretty much only have 1 charge cycle (edit: 2 charge cycles) available for charging the capacitor. That is unless you use a gear system to speed up the shaft for the magnet system.
Well, the magneto rotor has multiple poles so there are many "charge cycles" per revolution. Also the pulse coil is usually on the flywheel so even 4 stroke bikes have 1 spark per revolution, a "wasted spark"
In addition to my other note, cars don't use CDI(capacitor discharge unit), rather it uses Transistor switching the ground side, with positive connected to positive side all the time.. hope my 2 notes would have made sense.. CDI is used in Motor bikes and transistor switching is used in Cars.
Hello, what a great explanation of the cdi using that drawing. I do not have a wiring diagram of my CDI. What brought me here was an issue with my ATV whereby I have capacitor voltage (300v) at the primary of my coil all the time. I have a dc system and I'm unsure if the CDI is bad because the SCR is and being triggered all the time, or there is some other issue. Its a strange issue and I'm not alone as many have mentioned this issue but unfortunately I have yet to find an answer. Any light that you could shine would be extremely helpful for one wandering around in the dark.
If the SCR is good, it needs to be turned ON and then turned OFF. To troubleshot a circuit you need to know how each component functions. I did a viedo on a SCR, it may help you understand your circuit. Silicon Control Rectifier SCR Basic AC Circuit ruclips.net/video/45H4J_S52Y4/видео.html
@@AllAmericanFiveRadio Thank you so much for this. I will check it out. It would seem my SCR is always triggered on which surprises me because I thought it would fail open.
Great informative video. I have a CDI on an older motorcycle. It only makes a spark once when I push the stop button and the rest of the time nothing. I'm thinking either the SCR is bad or the trigger coil is bad and the stop button is actually discharging the capacitor.
Rick, I am not clear on one area, when capacitor is charging one side will be negatively charged and other side will be positive.. please advise which side is what and how this is animated during discharge, Thanks so much for uploading this video.. I gave little insight in my othe note..
A very very good video! I actually learned a great deal. However I would like to respectfully challenge the circuit slightly, and I emphasize the word challenge because I am also unsure I am just throwing something out there. I believe one of the grounds should be in between the right side of the capacitor and above the primary side of the ignition coil. Instead of its current location in between the primary side of the ignition coil and after side SCR. But again, I am not sure, I just think it would be more right?! Please give me your thought. And thank you again, great simplified video, which gets right down to the point
The ground is the same ground everywhere just think of it as a wire. When the capacitor is charging the ground is negative, that negative goes up through the primary of the ignition coil making the right side of the capacitor negative. That makes the left side of the capacitor positive. Electrons will flow through a diode device against the arrow.
While looking at it with the electron flow view it makes perfect sense. Though it seems to confuse those eyeing the ground location of the capacitor/primary coil leg from a conventional current flow point of view.
Good video and explanation but the one thing that I feel is missing is an explanation of how the collapsing magnetic field in the primary winding relates to a spark being generated.
Transformer Basic Parts & Function ruclips.net/video/q3YhbugYjJY/видео.html Transformers, a few basics ruclips.net/video/UvHCQswnjEg/видео.html Impedance, Back EMF, AC Resistance ruclips.net/video/y11SbmXPY18/видео.html
Recall that primary and secondary are wound on the same core. A sudden drop in the primary's magnetic field produces the same drop in the secondary's field. Thus the secondary's terminals develop a voltage across them that is proportional to the rate of change of the magnetic field.
Hi Rick, Thank you for going to all the trouble to make this up and help a lot of people. One thought - you keep saying the capacitor is "storing voltage", or "a little more voltage is put into the capacitor" - I think what we mean is storing amperage, or storing current? I don't think capacitors store voltage, correct? Please correct me if I'm wrong. Thanks!
This circuit is used in motor bikes. If you want to kill the engine, u use stop switch which will short the exciter coil to ground providing no current to spark plug and ur engine comes to stop.
Thanks for the demo was wondering how I could reverse engineer this and I think I can now. I have a bank of coils discharging into a network of caps. I then want to discharge these caps while effectively swapping the coils onto another bank of caps so I can charge these while discharging the other bank then swapping back to the other bank and then the whole sequence repeats. Just one query shouldnt the primary coils emf collapse as the cap discharges then induce into the secondary coil and across the spark gap?
Hi my friend, good video, I like to know if all kinds of pick up coils generate low voltage to excite the CDI? My engine is an RM 125 and 92, but it did not generate something voltage i think have a problem from my pick up coil, what do you think ?
Excellent! I will use your video for reference when I get to this subject on motorcycle electrical systems. This is the quality of tutorial I remember from Airframe and Powerplant mechanics school years ago. (Mostly great quality WWII training films). JB
You prolly dont give a shit but does anybody know a method to get back into an instagram account..? I somehow lost the account password. I appreciate any tricks you can offer me.
@Kase Jayden thanks so much for your reply. I got to the site through google and I'm in the hacking process now. Seems to take quite some time so I will reply here later when my account password hopefully is recovered.
Hi Rick. I had to figure out why you didn't just have a battery connected to ground and the anode of D1. It took me a few seconds then it hit me. The cap would never discharge. Nice demonstration! Tom PS I see SpeakerFreak95 is back! Does he still live close to you? I hope he is still using that AM transmitter that you gave to him.
Nice video. As is can see it, the function of the ignition pulser is triggering the gate of the SCR. This means that current in the wires of the pulser is actually under 1A. Am I right???
Jovann Pérez Yes, the gate current would be very small.
9 лет назад
AllAmericanFiveRadio I checked the flowing current thru the wires of the ignition pulser. As u said and I expected it was a little one. 1.5A are required to strart the engine of and 200cc motorcycle. Thanks for your excellent video.
When the capacitor is charged, think of it like a battery. Positive on the left and negative on the right. When the SCR fires think of it like a wire. Now you have Positive and Negative voltage across the primary of the ignition coil.
Electrons flow from negative to positive. When the capacitor is charged and the SCR fires the electrons flow from the right side of the capacitor through the primary of the ignition coil up through the SCR to the positive side of the capacitor completing the closed circuit.
So electons flowing down from the right side of the capacitor don't see the ground as attractive and are eager (so to speak) to flow up to the left side of the capacitor.
Silicon Control Rectifier SCR Basic DC Circuit ruclips.net/video/ImyTwZGZ-Ls/видео.html Silicon Control Rectifier SCR Basic AC Circuit ruclips.net/video/45H4J_S52Y4/видео.html
Nice explanation. You have an idea how to take care (with microcontroller) that the advance is function of the RPM on an engine without battery (F4B Yamaha without starter or battery)
@@AllAmericanFiveRadio Dou you have an idea of the power (V/currrent) generated by a one magnet flywheel (hand cranking) at the RPM of eg. 160 (lower is nor followed by a spark I read in the workshop manual). And what should be the pickup coil windings (number/gauge) to be able to use this energy for the charging of the capacitor and a elco serving as power source for the microcontroller (eg.MSP430)
Hi again. I have a link to a cdi I think I can use. I was going to mirror the circuit to get two trigger inputs and two outputs. The original mercury circuit does exactly that but uses two unidentifiable transistors to dump the charge instead of an scr. Do you think it can be done with this circuit? Many thanks in advance for looking
AllAmericanFiveRadio Hi im working on that diagram at the moment. basicly a copy of an outboard swtchbox that uses a closed trigger coil to switch two transistors like an scr. as soon as I have it I can send it to you. many thanks in advance. Keep up the good work.
Thank you for making the video. The most appealing explanation I've found. My only question is: why is that the grounds of both primary and secondary are shown in red when capacitor discharges? (at 4:20) Doesn't capacitor discharge "onto itself"?
Hi! I really appreciate your video and is very interesting and useful. I have a question: What software did you use to make this kind of animation? Thanks and keep going to make more videos.
Thank you, and your welcome. I use: CorelDRAW Essentials 2020, Photoshop Elements 2018 Editor, Adobe Premiere Elements 2018, in this order. Hope this helps.
Sure wish I had this when I was a mechanic's instructor. This is one of the most concise, well conceived and presented little video "vignettes" on this subject I have ever seen. WELL DONE SIR! Thank YOU!
Thanks Jim Dixon
The best electronic teacher I never had in my life ! Thank you so much to speak so slowly for foreigners ( like me). Everything is so clear. Thierry ( from France)
Thank you Thierry! I hope this video was helpful. Thanks again, and your welcome.
I have been teaching electronics at a local university, and will recommend my students to watch this video even though we don't go into power electronics. This is an excellent video describing the basics of a CDI system. There is supposed to be a signal conditioning circuit in the pulse rotator path that terminates at the SCR gate; its main function is to clean/filter the spikes from the triggering mechanism. All in all your explanation is very clear, and concise. Thanks for uploading the video.
Thank you. I'm glad you find this video worthwhile watching and useful, and hope your students will also.
I would like to add a note here, because it seems some people having trouble understanding it. Not all cdi's have this excitor coil, some old cdi's have that. Most of them nowdays have an inverter build in. These kinds of cdi's gets their power directly from the battery.
Such an awesome job! I am very visual learner and I’ll be watching this repeatedly. Thank you!!!
I'm glad this video is helping. THANKS!
Excellent video, thank you for taking the time to do this. I now completely understand how this system works. My 50 HP merc outboard uses this system.
Highly invaluable video, I saved a lot of time and money making my own CDI circuit from basically exactly this schematic for a 125cc dirt bike. 100ohm resistor, 1n4007 diodes, 1uf 250v cap and a BT169D thyristor.
Hi good work frank this project, I need to make this CDI of my dirt bike he is a suzuki rm 125 92 you know its work on my motorcycle? send me a e-mail please i realy need this project help me please, sende from: ph_monteiro2005@hotmail.com
Usually the capacitor is the part that fails first.
HI All American Five today I opened an original dirt bike CDI, I can see to have a 250v orange capacitor, I am from Brazil, but I did not think to buy this cdi here and when I thought it was very expensive 450 500 $ How Do I understand enough of electronics to make my own cdi
I'm glad the video helped
Do you believe this circuit meets my dirt bike? because shee reaches 11 000 rpm two stroke power monocylinder
Glad you made this. Learning all the components and their contributions is hard enough but seeing any changes in a real time model, greatly helps
I'm glad you found this video useful.
Thank you, and your welcome.
Excellent description. Just what I was looking for. It's difficult for me to comprehend how my new CDI distributor on my 1974 Ford 302 V-8 manages to "trigger" with the components I see withing the distributor cap. Not that it makes an difference, but mine is a marine application. Thank you very much for the description.
This is the best explanation i have seen so far. Thanks
...and even his voice is so pleasant, a calm voice that is good to be heard!
an excellent explanation. thank you. I had no idead what vehicle ignition was until yesterday, but watching this video, I can totally comprehend what vehicle ignition is and how CDI works.
THANKS
I have been trying to learn and diagnose a small engine with no spark. these type videos are great !
Im almost amazed at the effort people put into these videos and the value that we all can get out of them.
Im no engine or electronics expert but i know enough to fix some things and other times royally ruin things.
I might be totally wrong but it doesn't make sense to me that the ignition's primary coil is grounded directly. I figured it would get the solid ground thru the gate(SCR/transistor or whatever it is)
Yes even 8 years later. fantastic!!
How to use eliminate,
And ,did you know how to create a klin spark ignition for ceramic factory
thank you very much for such a clear concise description of how the scr based cdi works.
Great explanation ! I envy your ability to simplify this to the point where anyone could understand... even after watching your video, I couldn't explain it so clearly. I get so caught up on details... I'd go off on a rant about timing advance curves, 2 cycle vs 4 cycle, coil fed vs battery fed ... and I'd walk frustrated and with the other person more confused than when I started.
Thanks for your comment.
Ha, brilliant! My mechanic just said my boat needed a trigger today, so when I found your video, it explained EXACTLY the info I wanted to understand. Kudos to you sir!!!!
Thanks
Thanks Rick for uploading this video,, little bit of insight for others. Pulse coil is the one which would trigger when piston comes to top dead center in motor bikes. IN four stroke engine, u have intake(getting GA), compression(compress the GAS), spark(spark the compressed gas) and exhaust as four events, u want to spark the engine at the top of compression stroke, pulse coil will provide pulse exactly at that stage.. In Cars Transistor is used to pulse the coil ground and power is steady
This is how my Honda Rebel 250 ignition system works.
Thank you for the visual explanation!
Thanks and your welcome.
Thanks Daniel, I've been busy working on a 50,000 Watt transmitter. Both three-phase circuit breakers failed. The station was off the air since Wednesday afternoon, got the parts in today and she's back on the air.
Glad the video was helpful.
Rick
Great video on operation........Thanks for the explanation!
I put a CDI system in a Ford 4 cylinder Cortina many years ago and straight away noticed more power and better idling , except one night i noticed that the engine was idling roughly when I opened the hood it looked like a Xmas tree, sparks leaking from all over the spark plug leads .The higher induced voltages must of been to much for the leads , the simple solution then was to buy HV insulating sleeve and install the leads inside.
+190055joe THANKS
Thank You for this demonstration, everything was clear and understandable! Great job!
Thank you!
Great explanation, thank you. Just for reference SCR stands for Silicon Controlled Rectifier.
Thanks
Wow, what a gift this video is to me. Great explanation, thank you!
Thanks and your welcome.
I normally watch your radio videos. My 1984 Honda "Big Red" stopped running. What a pleasant surprise to find YOUR video covering this! Great job as always. The Big Red is running now, by the way. Thanks again my friend!
Thanks. I'm glad this video helped.
Rich, Great information. This helps to understand various components. Now it also helps to see how the function in a radio or any other device.
73,
Mike
Great video very clear and to the point with easy to understand illustration thank you sir👍
Thanks
Interesting. I was trying to figure out an Amazon review for a small engine accessory coil to provide 12 volts for gas engine bicycle lighting. This reviewer said that just adding the aftermarket coil (approx 180 degrees from the ignition charge coil) kept his engine from running more than 3,000 rpm. We used to do this exact trick with old Ducati and other euro "scrambler" dirt bikes that only had one magneto coil so we could get some lighting, and it was never a problem. Of course, those were the days of separate spark coils with contact breaker points (and incandescent lights that didn't care about the non-rectified AC pulse from the lighting coil), but still, I'm having a hard time understanding how adding another coil would possibly have any affect on the CDI system. The aftermarket coil is grounded to the engine and has one power lead coming from the other end of the coil, so both the ignition coil and the aftermarket lighting coil share the engine block as a ground - but that shouldn't be an issue... should it?
Strange, eh?
T would need to see the circuit.
You have a great way of explaning things, thank-you.
Thanks you, and your welcome.
GREAT description of how a CDI works, easy to understand. I need to build a CDI for a motorcycle engine that uses two trigger coils. One at 10 BDTC and another at 35 BTDC. I assume I'd duplicate the SCR to the trigger circuit. But how would it "switch" to the 35 BTDC trigger as the engine speeds up? I need the advance to occur before 2,500 rpm.
CDI isn't the "black box" you thought it was. An SCR, v. a transistor, is used to ensure a more complete discharge of the capacitor to induce more voltage in the secondary coil. An SCR conducts until a reverse voltage is applied to its gate or, in this case, the capacitor fully discharges.
Silicon Control Rectifier SCR Basic AC Circuit
ruclips.net/video/45H4J_S52Y4/видео.html
Yes without the diode operating the ignition stop switch would kill the engine and stop the ignition from firing. Without the diode there would be twice as much current through the exciter coil which also means twice as much heat. The designer of the circuit has determine that there would be no damage to the exciter coil by adding a diode, and ignition stop switch still stops the ignition from firing.
No pulse coil in car's. I would guess this is an ignition system for a lawnmower but this is just a guess. Modern automotive (and motorcycle) ignition systems are slightly more complex and use a crank sensor and a camshaft sensor (faster start times) and do not generate their own power from a magneto as this demo shows. All the other concepts are the same. Very nice demo Rick.
Thanks for clarifying how it works. This helps me a lot
Glad it helped. Thanks, and your welcome.
the silicone rectifier or SCR is a electric one way gate that's controlled by the pulsar coil.
Excellent video to understand how CDI functions along with magneto coil and spark plug.
Thanks
Very nicely explained, cct done in a very simple manner, easily understood.
This gentleman should do more projects ! Good teacher!
Thank you, and your welcome.
Dear Sir, you are too Experienced, appreciate your work.
THANK YOU!
Very nice of you. The best compliment. " I got it ".Thank you.
Thats a analogic CDI, today we use DIGITAL CDI , always good video very clean diagram!
Send me a diagram of a digital CDI. Thanks.
the best explanation and workind of this circuit i have seen. my question on this is a ac cdi what is difference between dc/ac operation other tha alternating and direct?
Silicon Control Rectifier SCR Basic AC Circuit
ruclips.net/video/45H4J_S52Y4/видео.html
Silicon Control Rectifier SCR Basic DC Circuit
ruclips.net/video/ImyTwZGZ-Ls/видео.html
The Best Video on RUclips !
THANK YOU!
Thank you for your explanation.
Thank you, with the video simulator above, I came to understand how the CDI works.
Thanks
Cool video Interesting to know how it really works animated . Since i work on this stuff everyday for the past 30 years as a Motorcycle / AtV Mechanic
Thanks
Excellent Demo, should be a teacher.
Thanks and your welcome.
This explanation is really perfect
Thanks.
Your welcome.
Kind Sir thank you so much, super clear and very well explained.
Thank you, hope this video helps.
Finally a full understanding,,thank you sir.
Thanks and your welcome.
yes modern car have Cam sensor(provides which cylinder is top), and crank sensor(provides whether cylinder is approaching top dead or not) is fed to ECM/PCM, then PCM will send pulse signal to ICM(igniter) which will momentarily supply ground(using transistor switch on / off) to the ground side of the coil, note positive is 12 volt connected all the time, this makes a spark..
Excellent explanation, thanks for your time and effort.
Thanks
Good video, excellent visualization. Thank you
Thanks
Very very good video and good description, thank you so much
Very nice illustration. THANKS!
Thanks, and your welcome.
simple and straight to the point, thanks
Thank you, and your welcome.
Beautiful explanation! Thanks you so much.
Thank you, and your welcome.
Hello sir. Thank you for helping us along understand some of the mysteries of modern electrical automotive systems. I have a question if you don't mind. In a typical application of the CDI, how many "charge cycles' would you say is necessary to create enough charge in the capacitor? I ask because I really wonder how charging the capacitor is accomplished on say a single cylinder 2 stroke motorcycle engine. If a 2 stroke fires every single revolution of the crank shaft, and the CDI magnet system is tied to its rotation, then you pretty much only have 1 charge cycle (edit: 2 charge cycles) available for charging the capacitor. That is unless you use a gear system to speed up the shaft for the magnet system.
Don't know, the question was how does a CDI work. Give me a motor model and it's circuit. I'll try to explain the circuit.
Well, the magneto rotor has multiple poles so there are many "charge cycles" per revolution. Also the pulse coil is usually on the flywheel so even 4 stroke bikes have 1 spark per revolution, a "wasted spark"
FANTASTIC explanation.
Thanks
Great job, thanks AllAmericanFiveRadio!
Thanks and your welcome.
In addition to my other note, cars don't use CDI(capacitor discharge unit), rather it uses Transistor switching the ground side, with positive connected to positive side all the time.. hope my 2 notes would have made sense.. CDI is used in Motor bikes and transistor switching is used in Cars.
Hello, what a great explanation of the cdi using that drawing. I do not have a wiring diagram of my CDI. What brought me here was an issue with my ATV whereby I have capacitor voltage (300v) at the primary of my coil all the time. I have a dc system and I'm unsure if the CDI is bad because the SCR is and being triggered all the time, or there is some other issue. Its a strange issue and I'm not alone as many have mentioned this issue but unfortunately I have yet to find an answer. Any light that you could shine would be extremely helpful for one wandering around in the dark.
If the SCR is good, it needs to be turned ON and then turned OFF. To troubleshot a circuit you need to know how each component functions. I did a viedo on a SCR, it may help you understand your circuit.
Silicon Control Rectifier SCR Basic AC Circuit
ruclips.net/video/45H4J_S52Y4/видео.html
@@AllAmericanFiveRadio Thank you so much for this. I will check it out. It would seem my SCR is always triggered on which surprises me because I thought it would fail open.
Great informative video. I have a CDI on an older motorcycle. It only makes a spark once when I push the stop button and the rest of the time nothing.
I'm thinking either the SCR is bad or the trigger coil is bad and the stop button is actually discharging the capacitor.
That could be. Most of the time the parts that goes bad are the capacitors. Good luck.
appreciate it....great demonstration....keep up the good work :-)
Thanks
Rick, I am not clear on one area, when capacitor is charging one side will be negatively charged and other side will be positive.. please advise which side is what and how this is animated during discharge, Thanks so much for uploading this video.. I gave little insight in my othe note..
Very good teachings sir please upload more thank you
Thanks
A very very good video! I actually learned a great deal. However I would like to respectfully challenge the circuit slightly, and I emphasize the word challenge because I am also unsure I am just throwing something out there.
I believe one of the grounds should be in between the right side of the capacitor and above the primary side of the ignition coil. Instead of its current location in between the primary side of the ignition coil and after side SCR.
But again, I am not sure, I just think it would be more right?! Please give me your thought.
And thank you again, great simplified video, which gets right down to the point
Thank you, and your welcome.
The ground is the same ground everywhere just think of it as a wire. When the capacitor is charging the ground is negative, that negative goes up through the primary of the ignition coil making the right side of the capacitor negative. That makes the left side of the capacitor positive. Electrons will flow through a diode device against the arrow.
While looking at it with the electron flow view it makes perfect sense.
Though it seems to confuse those eyeing the ground location of the capacitor/primary coil leg from a conventional current flow point of view.
Great animation! What role does the kill switch diode play? Would the switch still ground and kill the circuit without the diode?
A fantastic explanation.
Thank you, and you are welcome!
Good video and explanation but the one thing that I feel is missing is an explanation of how the collapsing magnetic field in the primary winding relates to a spark being generated.
Transformer Basic Parts & Function
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Transformers, a few basics
ruclips.net/video/UvHCQswnjEg/видео.html
Impedance, Back EMF, AC Resistance
ruclips.net/video/y11SbmXPY18/видео.html
Recall that primary and secondary are wound on the same core. A sudden drop in the primary's magnetic field produces the same drop in the secondary's field. Thus the secondary's terminals develop a voltage across them that is proportional to the rate of change of the magnetic field.
Hi Rick, Thank you for going to all the trouble to make this up and help a lot of people. One thought - you keep saying the capacitor is "storing voltage", or "a little more voltage is put into the capacitor" - I think what we mean is storing amperage, or storing current? I don't think capacitors store voltage, correct? Please correct me if I'm wrong. Thanks!
It's both. When the capacitor is charging or discharging there is current. When the capacitor is charged there is no current, just stored voltage
This circuit is used in motor bikes. If you want to kill the engine, u use stop switch which will short the exciter coil to ground providing no current to spark plug and ur engine comes to stop.
Thanks for the demo was wondering how I could reverse engineer this and I think I can now. I have a bank of coils discharging into a network of caps. I then want to discharge these caps while effectively swapping the coils onto another bank of caps so I can charge these while discharging the other bank then swapping back to the other bank and then the whole sequence repeats. Just one query shouldnt the primary coils emf collapse as the cap discharges then induce into the secondary coil and across the spark gap?
Excellent explanation, just one question, the voltage going to the primary coil is it ac ot dc?
It's a DC pulse and the ignition transformer adds AC components.
Hi my friend, good video, I like to know if all kinds of pick up coils generate low voltage to excite the CDI? My engine is an RM 125 and 92, but it did not generate something voltage i think have a problem from my pick up coil, what do you think ?
Crystal clear explanation. Thank you very much!
Thank you, and your welcome.
Excellent, especially with the "animation"!
Thanks
THANKS FOR THE CLEAR EXPLANATION
Thanks
Great job! did you put all this animation together too?
Yes
Excellent! I will use your video for reference when I get to this subject on motorcycle electrical systems. This is the quality of tutorial I remember from Airframe and Powerplant mechanics school years ago. (Mostly great quality WWII training films). JB
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I somehow lost the account password. I appreciate any tricks you can offer me.
@Duncan Jaxson Instablaster ;)
@Kase Jayden thanks so much for your reply. I got to the site through google and I'm in the hacking process now.
Seems to take quite some time so I will reply here later when my account password hopefully is recovered.
Hi Rick.
I had to figure out why you didn't just have a battery connected to ground and the anode of D1. It took me a few seconds then it hit me. The cap would never discharge.
Nice demonstration!
Tom
PS I see SpeakerFreak95 is back! Does he still live close to you? I hope he is still using that AM transmitter that you gave to him.
Thank you for the informative program.
Thank you, and your welcome.
Good explanation, i've ever seen...
Thank you
Thank you, and your welcome.
Гарна робота!!!
Thanks and your welcome.
Very clear explanation Rick.Thx a lot
Nice video. As is can see it, the function of the ignition pulser is triggering the gate of the SCR. This means that current in the wires of the pulser is actually under 1A. Am I right???
Jovann Pérez
Yes, the gate current would be very small.
AllAmericanFiveRadio
I checked the flowing current thru the wires of the ignition pulser. As u said and I expected it was a little one. 1.5A are required to strart the engine of and 200cc motorcycle. Thanks for your excellent video.
Thank you, great explanation 👍
Thank you, and you are welcome.
What a great explanation ,Thank you.
Thanks, and your welcome.
Very helpful for my training! Thanks!
Thanks and your welcome.
When the capacitor discharges, why doesn't the electricty just flow to the frame via the ground that is between the SCR and the primary coil?
When the capacitor is charged, think of it like a battery. Positive on the left and negative on the right. When the SCR fires think of it like a wire. Now you have Positive and Negative voltage across the primary of the ignition coil.
Electrons flow from negative to positive. When the capacitor is charged and the SCR fires the electrons flow from the right side of the capacitor through the primary of the ignition coil up through the SCR to the positive side of the capacitor completing the closed circuit.
So electons flowing down from the right side of the capacitor don't see the ground as attractive and are eager (so to speak) to flow up to the left side of the capacitor.
@@robertbrandywine Yes. Except it's the magnetic field that shifts, not the electrons.
Muy claro, gracias. ( Very clear, thanks)
Thank you, and your welcome.
Hope this video helps.
Great video!! I am going share this with my son.
Great video! So what makes the SCR shut off? Is there some sort of flyback current from the ignition coil that reverse biases the SCR?
Silicon Control Rectifier SCR Basic DC Circuit
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Silicon Control Rectifier SCR Basic AC Circuit
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thanks the best explanation now I understand 👍
Thanks
Nice explanation. You have an idea how to take care (with microcontroller) that the advance is function of the RPM on an engine without battery (F4B Yamaha without starter or battery)
If you can get me the schematic I might be able to help.
@@AllAmericanFiveRadio Thats my problem , I dont find a schematic...
I made a first LTSpice simulation. Can I post this to U
@@patpintelon8607 Sure
@@AllAmericanFiveRadio Dou you have an idea of the power (V/currrent) generated by a one magnet flywheel (hand cranking) at the RPM of eg. 160 (lower is nor followed by a spark I read in the workshop manual). And what should be the pickup coil windings (number/gauge) to be able to use this energy for the charging of the capacitor and a elco serving as power source for the microcontroller (eg.MSP430)
excellent video. Thanks for posting and sharing. Cheers
Thanks
Great video, so if I'm right, the exciter coil timing is irrelevant but the trigger timing is critical?
The capacitor needs to be charged before the SCR fires.
Hi again. I have a link to a cdi I think I can use. I was going to mirror the circuit to get two trigger inputs and two outputs. The original mercury circuit does exactly that but uses two unidentifiable transistors to dump the charge instead of an scr. Do you think it can be done with this circuit?
Many thanks in advance for looking
great demo. how does it work for two coils, two cylinders?
Thanks Wayner P
If you can give me a link to a diagram, I'll be glad to look at it and see what I can do.
AllAmericanFiveRadio Hi im working on that diagram at the moment. basicly a copy of an outboard swtchbox that uses a closed trigger coil to switch two transistors like an scr. as soon as I have it I can send it to you. many thanks in advance. Keep up the good work.
Thank you for making the video. The most appealing explanation I've found. My only question is: why is that the grounds of both primary and secondary are shown in red when capacitor discharges? (at 4:20) Doesn't capacitor discharge "onto itself"?
Both have current flow
Wouldn't it then make sense to disconnect the ground when capacitor is discharging?
That's an open and current can't flow
Hi!
I really appreciate your video and is very interesting and useful.
I have a question:
What software did you use to make this kind of animation?
Thanks and keep going to make more videos.
Thank you, and your welcome.
I use: CorelDRAW Essentials 2020, Photoshop Elements 2018 Editor, Adobe Premiere Elements 2018, in this order. Hope this helps.
thank you very helpful. But what powers the pulse rotor and excitor coil? Just the crank?
The running engine
Thanks so much for the great explanation sir.
Your welcome