I still do not udnerstand how this is driven. I was advised to try push/pull to make a beeper louder, but I am running with two AA batteries. If I were to split them like here to have +1.5V and -1.5V insted of doing 3V to 0V with a single mosfet, is there really any benefit?
Thanks for your comment. 3 volts is usually not enough voltage for a MOSFET. Here are a few videos that may help. Keep asking your questions! Simple MOSFET Experiment ruclips.net/video/otoeiVGu9uw/видео.html MOSFET Biasing Experiment ruclips.net/video/nA9BBv4tPc8/видео.html MOSFET Experiment ruclips.net/video/j47Yk7bJbxw/видео.html
@@AllAmericanFiveRadio sir can i ask something about the transistor outline 92 when the flat surface facing at you theres only two pin configuration weather its pnp or npn the left pin is emitter followed by collector and base and the other pin configuration from left is emitter, collector and base is my understanding is correct? tnx sir
@@boybravo689 To determine the pin out, use the transistor number and look up it's datasheet PDF. Example 2N2222 2N222 datasheet www.onsemi.com/pdf/datasheet/p2n2222a-d.pdf
Question why does this use all NPN transistors when I have read that it takes NPN and PNP to make a push pull amp? MY Pioneer amp has both NPN and PNP transistors for the final stage of amplification to the speakers. Also how is the signal amplified? Where exactly is that happening and how? Can you please show the point where the low power signal turns into high power signal. Is it the power supply 6V power supply that causes the boost?
Push pull circuits were developed first with vacuum tubes. You would have two vacuum tubes one on each half of the primary of the output transformer. One vacuum tube would conduct and then the other vacuum tube would conduct thus push pull. Vacuum tubes only worked one way and that happens to be very similar to NPN transistors. If you were to build the circuit you would find that it works exactly as depicted in this video. So another words there's more than one way to do many things. These video may help. Transistor, How Does it Work in a Circuit, Demo ruclips.net/video/vs3zUHdlsYY/видео.html Biasing an Audio Transistor ruclips.net/video/KtXE7s5DlcI/видео.html Transistor Amplifier for the Beginner, the basics ruclips.net/video/l-rfPfRgNJ8/видео.html
Is there a special reason for using the IRF510? The P-channel IRF9540 is complementary to the N-channel IRF540, so I would expect to see that in the positive stage. The input capacitance is very different between the 510 and the 9540, so it may have some influence on the symmetry.
Could you add capacitors into this circuit. If so, where? Also when I put loads at the rails the voltage is not stable. I only have the 24vdc supply and need stable +-12 V
Hi Rick I hope all's well with you. Another great video as ever. When you talked about 'strobing due to the camera frame rate' it reminded me of something I wanted to pass on to you. Someone recently told me that if you look at the infrared transmitter of a TV remote control with your mobile phone camera, when you press any button on the remote you will be able to detect the transmitted light beam at the diode. It certainly works with my Panasonic tv remote and Samsung phone camera. I hope that I remember it next time that I think the batteries have failed in the remote. 73's . . . Andy
Hey Andy, hope y’ll are doing well. I’m doing good and keeping busy. That very interesting, being able to seeing the IR from your TV with your phone. I’m going to try that. This reminds me of a IR experiment I want to try. Receiving audio from a vibrating services. I still have two unused IR Cootie detectors. Thanks Andy. 73…Rick
@@AndyDaviesByTheSea I may use this video clip because I never said what I was going to use this IR transceiver for. ruclips.net/video/oCDGfrQqMcI/видео.html
@@AllAmericanFiveRadio Ah i was confused about the FETs them selves, I tried making this circuit myself, but controlling the gates via a PWM signal to make a class D amp, but the N channel mosfet was barly working, and I think it was cause the load was on the source
@@X7cF4 I had this question about a month ago. The problem is that on the top MOSFET Gate, the pulse must be biased about 12VDC higher than the voltage that is on the MOSFET Source. The first video is about biasing the top MOSFET using a chip, no PWM just Frequency. The second video is an experimental circuit to bias the top MOSFET, with PWM and Frequency. Half bridge circuit ruclips.net/video/KthSMdA7VPc/видео.html Project ruclips.net/video/PkwqwKPnFpA/видео.html Good Luck!
is this a class a/b with mosfet in the output? i have several car amplifiers claiming to be class d topology but they really are like this design, ab with output mosfet
Great demonstration! Really helps to visualize what's going on here. I am curious about how the push pull is affected when changing the input volume from your audio source. Does one transistor turn off completely at a certain threshold or can the push pull action be maintained at at both high and low inputs somehow? I'm guessing the transformer version of a push pull doesn't have this issue...?
Both are possible, if both are always on, it's a class A amp. If not, it's class A/B. Whether you use a complimentary set-up or a phase inverting OT doesn't matter.
Hello, I'm trying to create a rail splitter using Op Amps. To draw more current and output power, BJT transistors in the form of complementary push-pull npn and pnp are used. Im trying to create the same thing but with Enhancment type complementary MOSFETs instead. It works the same way, but the problem is the mosfet gates are hard to bias and fully turn on, so the mosfets get very hot even with relatively small current draws. In both directions. The mosfets I'm using have a threshold of 4 volts. The gates are connected to the output of the Op Amp's output (the virtual ground). In theory and according to my measurments, the Op Amp's output should provide enough voltage to fully turn mosfets on for full push and pull current draws without even reaching the mosfets' absolute limits once a load is provided. Is there something I'm messing? Would it be possible for you to create a video on the subject? I haven't seen anyone do a high current MOSFET - Op Amp based rail splitter video. Oh, and I'm aware there are much better ways to split single supply rails or to have +/- supply rails. But I think this is a very simple and educational way to do a rail split. Maybe you would be interested in the subject :) Thank you for many great videos!
Thank you. I f ypu are looking for an on/off circuit you might consider IGBT. Insulated Gate Bipolar Transistor IGBT IKP06N60T ruclips.net/video/mL14VfjueIo/видео.html IGBT Astable Multivibrator ruclips.net/video/PnAiAhZH9hw/видео.html
@@SheikhN-bible-syndrome They will work for this type of determination. If you are building a audio amplifier, I would mach the specifications a little closer.
Why diodes? These are mosfets they dont have a .7 drop that needs to be overcome. In fact some mosfets dont even start to turn on until 1 or 2 volts. You could bias these with just resistors or a zener...?
Why diodes? Usually it's what I had on hand. I was building Amps for videos and got in the habit of using diodes. May not be necessary for MOSFET's. But there was no hikkup just above or just below Zero on the oscilloscope trace. I feel another video soon. Thanks for your question.
that was vety nice of you. you explained workings of power mosfet but can i use it as amplifier ? i was thinking of using such as power booster of my mini amplifier .
To drive a speaker requires more current. If you take a look at this Lafayette amplifier it is a good example of what you need. You can download the PDF from this page. Lafayette LR 200 www.hifiengine.com/manual_library/lafayette/lr-200.shtml
Very nice video. Thank you for displaying your simulaion of the AC load applied to the two green LEDs with a sinusoidal input signal. I take it the peak load applied to the two center-connected LEDs is 12V. What frequency did you use?
So the distortion in a dual-voltage source push-pull npn-pnp class B amplifier will disappear, when compensating diodes are in that place. OMG! Will it work with MOSFETS? Please share your opinion. Nice work.
This will produce audio but with a speaker it will have a weak output. More current is needed to drive a speaker. This Lafayette LR 200 receiver has a push pull transistor output although it is not MOSFET. If you download the manual you can see out the output transistors will draw more current to drive a speaker. Lafayette LR 200 manual www.hifiengine.com/hfe_downloads/index.php?lafayette/lafayette_lr-200_schematic.pdf
It would be a highly variable impedance. With no input, both MOSFETS will be turned off and the output impedance nearly infinite. With either MOSFET full on, the impedance would be nearly zero. what this means in real life depends on what you have connected it TO. Since there is no feedback, it also has no "damping ratio" and would be pretty bad for audio application.
Should function in a 'most responsive' manner. In October, they'll be remodeling a firehouse bunk room near where my cabin is located, and need an amplified, but not to the point of "blasting them out" speaker to monitor a non-dispatch radio frequency (chit-chat channel); this would probably work for that purpose. My only limiting factor is heat dissipation within the closed ceiling.
Not much difference, the low voltage off of zero is gone. AB realizes on transformer action to smooth the audio out and the distortion is at very low voltage.
In the schematic diagram the two diodesee are in the wrong polarity; for example the upper one (In the circuit diagram) Will prevent the positive half of the signal to pass to the N-Channel MOSFET..
Electrons flow from negative towards positive. Electrons flow against the arrow of a diode also resembled in a transistor/mosfet junction. So as you can see the top diode is forward biased allowing electrons to flow from the input towards the +12 supply via the 10k resistor.
@@LC-qi5ff Exactly, electrons flow against the arrow of a diode. From negative to positive. [Actually electrons don't flow, but that's another topic.] It's a difference between terminology/perception of engineering and physics.
@@LC-qi5ff "in that case the bottom diode is in the wrong direction" It is correctly shown. The diode creates a forward voltage drop of 0.6 volts, negative with respect to the source, and this -0.6 volts is applied to the gate, which acts like a vacuum tube; "pinches off" the current. incoming audio can drive it more negative, which does nothing since it is already pinched off, but on the positive swing of input allows the bottom MOSFET to conduct. The top MOSFET sees +0.6 volts on its gate, which pinches it off, and it uses the negative swing of input to turn it on. MOSFETS normally conduct and must be told to NOT conduct; this is like vacuum tube. Transistors normally do not conduct and must be told to conduct (by a small current from base to emitter).
I wish you had been my electronics teacher in the 70's, so well explained
A very good presentation😀.
Thank you, and your welcome.
thanks for this! I have been looking into and trying to learn amplifier design for a while, this makes the actual fundamentals finally click!
I’m glad this video has helped!!
Thank you, and your welcome.
I still do not udnerstand how this is driven. I was advised to try push/pull to make a beeper louder, but I am running with two AA batteries. If I were to split them like here to have +1.5V and -1.5V insted of doing 3V to 0V with a single mosfet, is there really any benefit?
Thanks for your comment. 3 volts is usually not enough voltage for a MOSFET. Here are a few videos that may help. Keep asking your questions!
Simple MOSFET Experiment
ruclips.net/video/otoeiVGu9uw/видео.html
MOSFET Biasing Experiment
ruclips.net/video/nA9BBv4tPc8/видео.html
MOSFET Experiment
ruclips.net/video/j47Yk7bJbxw/видео.html
Thumbs up done sir i have no training in tech school but because of your video tutorial i learned so much more power to your channel sir tnx
Thank you, and your welcome,
@@AllAmericanFiveRadio sir can i ask something about the transistor outline 92 when the flat surface facing at you theres only two pin configuration weather its pnp or npn the left pin is emitter followed by collector and base and the other pin configuration from left is emitter, collector and base is my understanding is correct? tnx sir
@@boybravo689 I do not understand what 92 is
@@AllAmericanFiveRadio sir the small plastic transistor which is transistor outline 92 or 92 package type sir tnx
@@boybravo689 To determine the pin out, use the transistor number and look up it's datasheet PDF.
Example 2N2222
2N222 datasheet
www.onsemi.com/pdf/datasheet/p2n2222a-d.pdf
Question why does this use all NPN transistors when I have read that it takes NPN and PNP to make a push pull amp? MY Pioneer amp has both NPN and PNP transistors for the final stage of amplification to the speakers. Also how is the signal amplified? Where exactly is that happening and how? Can you please show the point where the low power signal turns into high power signal. Is it the power supply 6V power supply that causes the boost?
Push pull circuits were developed first with vacuum tubes. You would have two vacuum tubes one on each half of the primary of the output transformer. One vacuum tube would conduct and then the other vacuum tube would conduct thus push pull. Vacuum tubes only worked one way and that happens to be very similar to NPN transistors. If you were to build the circuit you would find that it works exactly as depicted in this video. So another words there's more than one way to do many things.
These video may help.
Transistor, How Does it Work in a Circuit, Demo
ruclips.net/video/vs3zUHdlsYY/видео.html
Biasing an Audio Transistor
ruclips.net/video/KtXE7s5DlcI/видео.html
Transistor Amplifier for the Beginner, the basics
ruclips.net/video/l-rfPfRgNJ8/видео.html
Thank you for uploding these videos, keep going!
Thank you, and your welcome.
Is there a special reason for using the IRF510? The P-channel IRF9540 is complementary to the N-channel IRF540, so I would expect to see that in the positive stage. The input capacitance is very different between the 510 and the 9540, so it may have some influence on the symmetry.
THAT IS THE PARTS i HAVE ON HAND.
Could you add capacitors into this circuit. If so, where? Also when I put loads at the rails the voltage is not stable. I only have the 24vdc supply and need stable +-12 V
What is it your wanting to do?
Hi Rick I hope all's well with you. Another great video as ever. When you talked about 'strobing due to the camera frame rate' it reminded me of something I wanted to pass on to you. Someone recently told me that if you look at the infrared transmitter of a TV remote control with your mobile phone camera, when you press any button on the remote you will be able to detect the transmitted light beam at the diode. It certainly works with my Panasonic tv remote and Samsung phone camera. I hope that I remember it next time that I think the batteries have failed in the remote.
73's . . . Andy
Hey Andy, hope y’ll are doing well. I’m doing good and keeping busy. That very interesting, being able to seeing the IR from your TV with your phone. I’m going to try that. This reminds me of a IR experiment I want to try. Receiving audio from a vibrating services. I still have two unused IR Cootie detectors.
Thanks Andy.
73…Rick
Hi Rick, glad that you are well. Rick, what the heck is a Cootie detector??
. . . Andy @@AllAmericanFiveRadio
@@AndyDaviesByTheSea I may use this video clip because I never said what I was going to use this IR transceiver for.
ruclips.net/video/oCDGfrQqMcI/видео.html
How come the load is at the source? Wouldnt that stop the gate from triggering?
If you are confused by the Compensating Diodes.
This video may help.
Crossover Biasing Compensating Diodes
ruclips.net/video/v2mITbaCHUE/видео.html
@@AllAmericanFiveRadio Ah i was confused about the FETs them selves, I tried making this circuit myself, but controlling the gates via a PWM signal to make a class D amp, but the N channel mosfet was barly working, and I think it was cause the load was on the source
@@X7cF4 I had this question about a month ago. The problem is that on the top MOSFET Gate, the pulse must be biased about 12VDC higher than the voltage that is on the MOSFET Source. The first video is about biasing the top MOSFET using a chip, no PWM just Frequency. The second video is an experimental circuit to bias the top MOSFET, with PWM and Frequency.
Half bridge circuit
ruclips.net/video/KthSMdA7VPc/видео.html
Project
ruclips.net/video/PkwqwKPnFpA/видео.html
Good Luck!
@@AllAmericanFiveRadio Thankyou
is this a class a/b with mosfet in the output? i have several car amplifiers claiming to be class d topology but they really are like this design, ab with output mosfet
I got as close to Class A as I could.
Thank you for the great video on push-pull amplifiers.
Thanks
Great demonstration! Really helps to visualize what's going on here. I am curious about how the push pull is affected when changing the input volume from your audio source. Does one transistor turn off completely at a certain threshold or can the push pull action be maintained at at both high and low inputs somehow? I'm guessing the transformer version of a push pull doesn't have this issue...?
Both are possible, if both are always on, it's a class A amp. If not, it's class A/B. Whether you use a complimentary set-up or a phase inverting OT doesn't matter.
The peaks are higher with more volume, and the peaks are lower with less volume.
In a totem-pole arrangement like this, if you ever turn on both transistors at the same time they will be destroyed.
Hello,
I'm trying to create a rail splitter using Op Amps. To draw more current and output power, BJT transistors in the form of complementary push-pull npn and pnp are used.
Im trying to create the same thing but with Enhancment type complementary MOSFETs instead.
It works the same way, but the problem is the mosfet gates are hard to bias and fully turn on, so the mosfets get very hot even with relatively small current draws. In both directions.
The mosfets I'm using have a threshold of 4 volts. The gates are connected to the output of the Op Amp's output (the virtual ground).
In theory and according to my measurments, the Op Amp's output should provide enough voltage to fully turn mosfets on for full push and pull current draws without even reaching the mosfets' absolute limits once a load is provided.
Is there something I'm messing?
Would it be possible for you to create a video on the subject? I haven't seen anyone do a high current MOSFET - Op Amp based rail splitter video.
Oh, and I'm aware there are much better ways to split single supply rails or to have +/- supply rails.
But I think this is a very simple and educational way to do a rail split. Maybe you would be interested in the subject :)
Thank you for many great videos!
Thank you. I f ypu are looking for an on/off circuit you might consider IGBT.
Insulated Gate Bipolar Transistor IGBT IKP06N60T
ruclips.net/video/mL14VfjueIo/видео.html
IGBT Astable Multivibrator
ruclips.net/video/PnAiAhZH9hw/видео.html
Great explanation, I'm wondering would this push pull amp also work at 100V and 1MHz? (And using 1MOhm instead of 100k)
you would have to modify the circuit. Use 100V plus MOSFET's
1mhz freq is RF . then youneed rf techniques. find RF linear amplifer at vu3inj.blogspot.com
@@AllAmericanFiveRadio could A1941 and C5198 transistors be adequate?
@@SheikhN-bible-syndrome They will work for this type of determination. If you are building a audio amplifier, I would mach the specifications a little closer.
how will the input signal get to the gate when the diode is reversed biased at positive cycle?
The two compensating diodes are biased ON. Biased ON they are just a wire, so the signal flows as it does on a wire.
Why diodes? These are mosfets they dont have a .7 drop that needs to be overcome. In fact some mosfets dont even start to turn on until 1 or 2 volts. You could bias these with just resistors or a zener...?
Why diodes? Usually it's what I had on hand. I was building Amps for videos and got in the habit of using diodes. May not be necessary for MOSFET's. But there was no hikkup just above or just below Zero on the oscilloscope trace. I feel another video soon. Thanks for your question.
Thanks Rick, a quick question...Could parallel mosfets be configured to obtain more power in this circuit? Regards
Thank you. Yes you could parallel them. Today you should be able to find MOSFETs that can handle the power you require.
that was vety nice of you. you explained workings of power mosfet but can i use it as amplifier ? i was thinking of using such as power booster of my mini amplifier .
To drive a speaker requires more current. If you take a look at this Lafayette amplifier it is a good example of what you need. You can download the PDF from this page.
Lafayette LR 200
www.hifiengine.com/manual_library/lafayette/lr-200.shtml
Very nice video. Thank you for displaying your simulaion of the AC load applied to the two green LEDs with a sinusoidal input signal. I take it the peak load applied to the two center-connected LEDs is 12V. What frequency did you use?
One Hz
Does this mosfets combination drive square wave pwm to step up transformer ? Reply me fast
Pulse Width Modulation Half Bridge MOSFET Driver TL494 2N2222 IRF510
ruclips.net/video/nTETbbn-dig/видео.html
Can igbt transistors be biased with the same diode setup as the mosfets?
It should work
@@AllAmericanFiveRadio thanks, I appreciate the answer.
So the distortion in a dual-voltage source push-pull npn-pnp class B amplifier will disappear, when compensating diodes are in that place. OMG! Will it work with MOSFETS? Please share your opinion. Nice work.
These are MOSFETS. Works with junction transistors also.
What is the usage of the variable resistor can i replace it with fixed one ?
You can ones you know the correct value. It there to set the bias.
Does it amplifies audio signal
This will produce audio but with a speaker it will have a weak output. More current is needed to drive a speaker. This Lafayette LR 200 receiver has a push pull transistor output although it is not MOSFET. If you download the manual you can see out the output transistors will draw more current to drive a speaker.
Lafayette LR 200 manual
www.hifiengine.com/hfe_downloads/index.php?lafayette/lafayette_lr-200_schematic.pdf
Thanks for reply sir
I wonder what sort of output impedance that setup would be.......
With Diodes impedance would be very low, they start to conduct at 0.6VDC. With speaker the impedance is 8 Ohms.
It would be a highly variable impedance. With no input, both MOSFETS will be turned off and the output impedance nearly infinite. With either MOSFET full on, the impedance would be nearly zero.
what this means in real life depends on what you have connected it TO. Since there is no feedback, it also has no "damping ratio" and would be pretty bad for audio application.
Just wondering if germanium diodes the 0.3V kind necessary for the crossover or if you can use regular 0.7V diodes?
Silicon transistors,so silicon diodes, about 0.6VDC
Thanks much. Best explanation on the web.
Thanks
Should function in a 'most responsive' manner. In October, they'll be remodeling a firehouse bunk room near where my cabin is located, and need an amplified, but not to the point of "blasting them out" speaker to monitor a non-dispatch radio frequency (chit-chat channel); this would probably work for that purpose. My only limiting factor is heat dissipation within the closed ceiling.
Thanks
The input is what voltage?....and the wave input how is?
2volt Sine Wave
Mantab..good vidio
Thanks
How different it works to a class ab amplifier?
Not much difference, the low voltage off of zero is gone. AB realizes on transformer action to smooth the audio out and the distortion is at very low voltage.
Excellent video thank you for the care you put on creating these, the are imensly helpful
Thanks
I Second That. 🤓Time To Get My Nerd On
Back To The Lab.
In the schematic diagram the two diodesee are in the wrong polarity; for example the upper one (In the circuit diagram) Will prevent the positive half of the signal to pass to the N-Channel MOSFET..
Crossover Biasing Compensating Diodes
ruclips.net/video/v2mITbaCHUE/видео.html
Electrons flow from negative towards positive. Electrons flow against the arrow of a diode also resembled in a transistor/mosfet junction. So as you can see the top diode is forward biased allowing electrons to flow from the input towards the +12 supply via the 10k resistor.
@@DrHarryT in that case the bottom diode is in the wrong direction
@@LC-qi5ff Exactly, electrons flow against the arrow of a diode. From negative to positive. [Actually electrons don't flow, but that's another topic.] It's a difference between terminology/perception of engineering and physics.
@@LC-qi5ff "in that case the bottom diode is in the wrong direction"
It is correctly shown. The diode creates a forward voltage drop of 0.6 volts, negative with respect to the source, and this -0.6 volts is applied to the gate, which acts like a vacuum tube; "pinches off" the current. incoming audio can drive it more negative, which does nothing since it is already pinched off, but on the positive swing of input allows the bottom MOSFET to conduct.
The top MOSFET sees +0.6 volts on its gate, which pinches it off, and it uses the negative swing of input to turn it on.
MOSFETS normally conduct and must be told to NOT conduct; this is like vacuum tube. Transistors normally do not conduct and must be told to conduct (by a small current from base to emitter).
Nice display Rick,,, thanks'
Thank you, and your welcome.
Thank you very much great for an amateur like me.
Thanks
Great Video, thank you allamericanfiveradio.
Thanks and your welcome.
Nice presentation . Thanks.....
Thank you, and your welcome.
Very well demonstrated.
Thanks
I understand how it works now! Yes! I am a visual learner!
Thank you
@@AllAmericanFiveRadio The pleasure is mine.
Amazing video 😍
Thanks
Thanks 😊👍🙏💯
Thank you, and your welcome.
Thank you
Thank you, and your welcome.
Super!!!
Thanks
👏👏👏👏👏👍
Thanks!
👍👍👍🙏🙏🙏 Great !!!! Thanks !!!!
Thank you, and your welcome.
😀@@AllAmericanFiveRadio
GOOD........
THANKS