Very nice! As an extra safety precaution put a 1N400x diode across the 7809. The cathode of the diode (side with the band) goes to the input side and the anode goes to the output side. That will save you from a spark or inrush current taking out the voltage regulator. They are then pretty well impossible to destroy. I buy 2.5 amp 2,000 volt rectifiers very cheap in bulk and keep a nice bunch for such occasions. Btw, I received my teaching degree in Industrial Arts, electronics from Southeast Missouri State University in 1978. I’m an old fart! But my Elmer never finished high school! He knows more about electronics than I will ever know! Degrees are just a piece of paper.
The problem that was found is this, let’s say that you are driving the coil of a 9 volt relay with this circuit. When the coil of the relay is energized, there is a high voltage pulse produced that goes backwards towards the power supply. It can be high enough to give you a nice shock. When that high voltage pulse occurs on the output side of a 78xx series, it can quickly destroy that voltage regulator. High current doesn’t do it, a backwards high voltage pulse does it. The regulator I.C. isn’t capable of handling that backwards high voltage. After all, the output voltage is supposed to be lower than the input. So pop! That I.C. gets destroyed faster than an MRF-454 with high SWR! The fix is that rectifier across the I.C. as I described. In fact, the notes from Fairchild recommended that diode when you could be dealing with inductive loads. Also, if this circuit is located more than a couple of feet from your power supply, put a tantalum capacitor of about .1 mf from pin 1 to ground. Keep the voltage rating of that tantalum above what you anticipate the voltage input to be. There can be a high frequency oscillation set up when these longer input leads are involved. That capacitor you talked about from pin 1 to ground is fine, but it actually looks like a high impedance at high frequency. I have ran into that condition several times in my life. Just do those two things and you won’t have to learn a hard lesson. I have more LM7808 regulators laying around than 7809. So I put two high voltage rectifiers in series. Lift lead #2 from ground and put them from pin 2 to ground. The cathode goes to the ground. That will add 1.4 volts to the regulator output and you will have 8 volts plus 1.4 volts, or 9.4 volts regulated output from your circuit. Easy as pie! If you need more current, you can use a larger regulator I.C. or you can use this circuit to set a voltage and then a pass transistor to handle higher current. Many design manuals list such circuits. There is no end to the fun you can have, building and modifying circuits. It can save you money, you learn something, and impress the heck out of friends!😊 I built my own power supplies, power mics, antenna tuners, antennas, and built a fun career! For me it all started in the late 60’s with a magazine of circuits and very little money. Just do it guys!
9 VDC is awesome But 5 VDC is even cooler for USB powered stuff. I have noticed lately that I have had to build a lot of 5VDC stuff. I wanted to charge my phones and radios in the trailer so I built some to hard wire built-in permanent stuff.
Thanks for taking the time to make this video. This is a great circuit for a guy who wants to run his 9v base battery operated mic and not use a battery.
Have a Happy Thanksgiving wagonmaster I got my new antenna up it's working fantastic I got to do more work to it when my friend gets in time I'll be able to put in my two element beam up in there I can't wait to get it up in the sky I'm just sitting back having a coffee and listening to the band it's amazing this antenna picks up really good
That requires a more, complex circuit. I have used a couple of transistors, set up as a high frequency oscillator, going to a toroid core for the primary. Then I wind the secondary on the toroid with a center tap, so I can use two diodes to produce the full wave output and go to a filter capacitor. But the rectifiers MUST be high frequency types. The 1N4xxx series can’t handle high frequency! You wind the secondary to get a voltage of 18-20 volts d.c. Then use a 7815 to regulate it to 15 volts. Clear as mud?
@@390WagonMasterThe torpid cores are available on line. The more wattage you require, the bigger the toroid must be. But it is worth the effort you can wind a big power supply for tube mobile linears if you like. The secondary of the torpid transformer can be wound to almost any voltage. It’s a great thing!
No. Those silicon rectifiers only drop the voltage by .7 volts each. So it takes much more than two to get a 3 volt drop. On top of that, if you are dealing with automotive voltages, they vary wildly. The 7809 will maintain that output voltage as long as it receives at least 11 volts input to it. A couple of volts are needed above the rated voltage on the LM78xx series of voltage regulators. Check out the Fairchild design manual for linear voltage regulators. Wagonmaster knows what he is doing and his circuit is perfectly workable as it is. Just a couple of little improvements could be made so that it isn’t as apt to die. And never forget what Wayne Green used to say, “Never Say Die” huh Wagonmaster?🤣
Very nice! As an extra safety precaution put a 1N400x diode across the 7809. The cathode of the diode (side with the band) goes to the input side and the anode goes to the output side. That will save you from a spark or inrush current taking out the voltage regulator. They are then pretty well impossible to destroy. I buy 2.5 amp 2,000 volt rectifiers very cheap in bulk and keep a nice bunch for such occasions.
Btw, I received my teaching degree in Industrial Arts, electronics from Southeast Missouri State University in 1978. I’m an old fart! But my Elmer never finished high school! He knows more about electronics than I will ever know! Degrees are just a piece of paper.
I have a 1A fuse on my bench 12V out so I'm not worried about problems. This 7809 is only good for 1.2 A so IMO this device is (Internally fused) Hihi
The problem that was found is this, let’s say that you are driving the coil of a 9 volt relay with this circuit. When the coil of the relay is energized, there is a high voltage pulse produced that goes backwards towards the power supply. It can be high enough to give you a nice shock. When that high voltage pulse occurs on the output side of a 78xx series, it can quickly destroy that voltage regulator. High current doesn’t do it, a backwards high voltage pulse does it. The regulator I.C. isn’t capable of handling that backwards high voltage. After all, the output voltage is supposed to be lower than the input. So pop! That I.C. gets destroyed faster than an MRF-454 with high SWR! The fix is that rectifier across the I.C. as I described. In fact, the notes from Fairchild recommended that diode when you could be dealing with inductive loads. Also, if this circuit is located more than a couple of feet from your power supply, put a tantalum capacitor of about .1 mf from pin 1 to ground. Keep the voltage rating of that tantalum above what you anticipate the voltage input to be. There can be a high frequency oscillation set up when these longer input leads are involved. That capacitor you talked about from pin 1 to ground is fine, but it actually looks like a high impedance at high frequency. I have ran into that condition several times in my life. Just do those two things and you won’t have to learn a hard lesson.
I have more LM7808 regulators laying around than 7809. So I put two high voltage rectifiers in series. Lift lead #2 from ground and put them from pin 2 to ground. The cathode goes to the ground. That will add 1.4 volts to the regulator output and you will have 8 volts plus 1.4 volts, or 9.4 volts regulated output from your circuit. Easy as pie!
If you need more current, you can use a larger regulator I.C. or you can use this circuit to set a voltage and then a pass transistor to handle higher current. Many design manuals list such circuits. There is no end to the fun you can have, building and modifying circuits. It can save you money, you learn something, and impress the heck out of friends!😊
I built my own power supplies, power mics, antenna tuners, antennas, and built a fun career! For me it all started in the late 60’s with a magazine of circuits and very little money. Just do it guys!
9 VDC is awesome
But 5 VDC is even cooler for USB powered stuff.
I have noticed lately that I have had to build a lot of 5VDC stuff. I wanted to charge my phones and radios in the trailer so I built some to hard wire built-in permanent stuff.
I made one up with the 7805 for my Bluetooth receiver in my truck. I heat shrunk that as well.
Thanks for taking the time to make this video.
This is a great circuit for a guy who wants to run his 9v base battery operated mic and not use a battery.
Thats nicely done .
Very COOL!!!💯🙂👍
Have a Happy Thanksgiving wagonmaster I got my new antenna up it's working fantastic I got to do more work to it when my friend gets in time I'll be able to put in my two element beam up in there I can't wait to get it up in the sky I'm just sitting back having a coffee and listening to the band it's amazing this antenna picks up really good
Happy Thanksgiving! Sounds like you’ve got a great setup going.
I think this is some good learnin.
can you show how to step up from 13.8 volts to 15 volts Just a small isolated step
That requires a more, complex circuit. I have used a couple of transistors, set up as a high frequency oscillator, going to a toroid core for the primary. Then I wind the secondary on the toroid with a center tap, so I can use two diodes to produce the full wave output and go to a filter capacitor. But the rectifiers MUST be high frequency types. The 1N4xxx series can’t handle high frequency! You wind the secondary to get a voltage of 18-20 volts d.c. Then use a 7815 to regulate it to 15 volts. Clear as mud?
Yea, I don't have the parts to build one. (Inductors)
@@390WagonMasterThe torpid cores are available on line. The more wattage you require, the bigger the toroid must be. But it is worth the effort you can wind a big power supply for tube mobile linears if you like. The secondary of the torpid transformer can be wound to almost any voltage. It’s a great thing!
@@390WagonMaster I just wanted to up my station voltage to include the amplifier.
Upgrade your power supply, there is not a circuit like this or module to handle that kind of amperage draw.
EDIT.... That I know of.
You should only use 100 nF on the 9 volt side. With a big capacitor the regulator can go into overload protection.
@@michaellundsrensen2292 good to know.
OR?? add in 2 series 1n400 * diodes in the 12v output ....to reduce Voltage by 3 volts. Naww too easy.
A few ways to get the job done for sure. Just shoeing one of those ways. Besides, who doesn't love a fun quick and easy project? Hihi
No. Those silicon rectifiers only drop the voltage by .7 volts each. So it takes much more than two to get a 3 volt drop. On top of that, if you are dealing with automotive voltages, they vary wildly. The 7809 will maintain that output voltage as long as it receives at least 11 volts input to it. A couple of volts are needed above the rated voltage on the LM78xx series of voltage regulators. Check out the Fairchild design manual for linear voltage regulators.
Wagonmaster knows what he is doing and his circuit is perfectly workable as it is. Just a couple of little improvements could be made so that it isn’t as apt to die. And never forget what Wayne Green used to say, “Never Say Die” huh Wagonmaster?🤣