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Very nice and clear presentation. Thank you very much. One good presentation is much more efficient for a beginner than reading 10 pages of silly text, and gives appetite for further helpful reading if needed.
Why can't all tutorials be like this? Expanding slightly on the circuit construction would be the only added benefit here I can see. Kudos +Afrotechmods
I built a PWM circuit using your diagram to control current flowing through a non-inductive piece of nichrome wire. Works like a charm. I picked a TIP141 NPN Power Transistor. Before using the 555 I tested it with a function generator and discovered the optimal switching frequency for PWM was about 1khz (close to what you have). In the datasheet TIP141 lists switch on time as 0.9μs and switch off as 11μs. I figured that by adding the values I'd get a full cycle of 11.9μs and a bandwidth cap of 84Khz, yet when cranking up the function generator, I found the real bottleneck to be closer to 8Khz. Pass that TIP141 wasn't able to keep up. Am I calculating the full cycle wrong is the discrepancy caused by the fact my test conditions (load and base-emitter voltage) being different from those in the TIP141 datasheet?
@blacklust007 Excellent question. The LM317 is a linear voltage regulator which is inherently inefficient. It burns up excess voltage as heat to get the output voltage you want. Power loss will be (Vin - Vout) * Iout. PWM is switching between fully off and fully on, so it will be much more efficient and generate less heat.
@nonodalloo The main thing that will determine the current limit is the transistor you use. You should try find a low resistance N channel MOSFET, put a heatsink on it, and get a schottky diode rated for 5A to put in antiparallel with the motor.
@jwhill15 Sure. Use a separate power supply for the 555, (roughly 10V will do) and then 24V will go on the high side of the motor. Make sure the grounds are all connected.
The PWM output goes though an inductor to a capacitor to filter the waveform into DC. Usually there is a Zener diode to clamp the voltage, but the efficiency is still really good at 80 - 90 percent. Look up the LT3505 chip for a typical example.
You are the god of electronics , I simply am so attracted to the way you teach, that I would like to be your disciple for life. Thanks for the video that is to the point.
Awesome video. I already knew a fair amount about PWM and controlling it, but I needed something simple (ie a 555 circuit) for a single direction, single motor project, and this will work perfectly. Thanks much!
Hey, very good explanation and good images.. one can with good benefits replace the NPN Bipolar Transistor that you show on the image with a mosfet.. some of the main benefits are. Eliminate the input resistor (known as a base resistor on a BJT) Allowed faster switching speeds. Lower on resistance In most cases cheaper Lower risk of thermal runaway (due to the thermal behaviour of a Mosfet) Note that it is not possible to have a 0 to 100% duty cycle with only a 555.
@spelunkerd If you energize a coil like in a motor, what happens is, you establish a magnetic field across it. When the power pulse goes away, the field collapses back across the windings, inducing a voltage back across the coil. Depending the value of that coil, it can be a fairly high voltage. That voltage can destroy your transistor or FET so the diode blocks such voltage and sends it back to the coil to be dissipated instead of across your transistor. This effect is called "back EMF".
I tried this with a TLC555 and nope doesn't work! I kept trying and couldn't get it. So finally I ordered an NE555 and sure enough! it went from 0.2% to 99.9%! Lol, I guess you weren't kidding when you said it won't work will an TLC555. I'am gonna use this on my DIY electric go kart. Thanks Afrotechmods!
@spelunkerd Also what the diode does is help eliminate what are called eddy currents. Eddy currents flow any direction within a magnetic medium. These fields will collide with and interupt the fields that the control source feeds into it. At these areas of colision, heat is generated, and sometimes, lots of heat. Designers of motors and transformers design spacific shapes and other things into the magnetic medium, to eliminate eddy currents, thus reducing heat buildup.
ok, this make's more logic to me. I am fighting with a pwm circuit now for 2 months, and all burned out. So now i will try this circuit, it looks more solid to me.
Change C1 to a lower value to raise the frequency. I'm not sure what the lower bound of the cap value is though. Any frequency above 20Khz or so will be inaudible. If you were using this circuit to control a motor, you could set the switching speed to something like 25Khz and you wouldn't hear a "switching whine."
@tjnlsn255 Both ways will work. But I would use the LM317 method because a stable voltage over time will mean the frequency and duty cycle won't drift as the batteries discharge.
This capacitor shorts out the inductive spike created by the motor starting or stopping. This spike could damage other circuitry. Notice that the diode should be reversed biased to the power applied to the motor. The inductive kick of the motor is of opposite polarity and therefore is dissipated through the diode! It's been a while for me in circuit building but this same principle is used with relays and was used extensively in the stepping relay in the old 8 track tape decks. I hope this helps!
@Landotter1 What you will need to add is a biasing resistor to the drain of each of the FETs or the emitter of the bipolar transistors. This resistor should be roughly .1 - .5 ohm 5 - 10 Watts. Radio Trash used to sell them but I don't know, these days. Any hifi repair shop will stock them too. Any blown up power amp will have them. In the hifi world, they are called "emitter resistors"
thank you. cool stuff. it was of particular utility for you to mention that it works up to ~15v. that pre-empted my question concerning whether this would be safe to use with an SLA such as in a car, where it could be up to13.6v or so.
How about doing a part 2 vid on basics on feedback so when heavy loads are applied, the duty cycle will increase to a set value and change back to low load value and no baby sitting. Think a 556 timer will do that right? I forgot...
Fantastic tutorial! very clearly explained, but a few questions; how many led's could you control using this PWM? (Im looking at controlling a large array of leds) Also, could this pwm control a 12v motor without any troubles?
in your video you have the 555 timer and the led's being powered by the same 12v source. When you Modulated that into a lower voltage signel wouldn't that also lower the voltage feeding the 555 timer.
Wow I just learned something lol. That actually made a lot of sense. I have a question, do lift switch dimmers use PWM too? Is this why CFL bulbs tend to flicker? If so, would using multiple step down transformers (though impractical) to lower the voltage make a CFL bulb dimmer without flicker?
OMG THIS IS MUCH MUCH EASY TO UNDERSTAND :))))) compare to my lecturer who yelled at us :" GO BACK TO PRIMARY SCHOOL IF U DONT UNDERSTAND WHAT I'M TALKING!!" :D
@Afrotechmods Thanks for that well explained answer :) is this the same method used for the PWM fan control system used by current computer motherboards?
It´s good, but Can you put the circuit diagram or another link to watch it please? Really thank you. Just I got a trouble With the resistence bulbs, we see an annoying flicker.
@Afrotechmods So technically, there is no limit to the amount of Voltage & Current one can PWM with the 555 timer IC, as long as your electronic components are electrically capable on the high side of the motor? Then in that case you would switch it "on" & "off" (like your transistor video) or using an IGBT (Insulated-Gate Bipolar Transistors) [Which btw, some can even go as high as a rated current of 1,200A & a maximum voltage of 3,300V] or a relay for heavier loads. :)
Awesome video!!! I have been searching the web to see if I can get an answer to this question: If I connect 120v AC mains through a transformer with a 1:1 wind ratio, then through a full wave rectifier, can I PWM the resulting voltage to control the speed of a 1200 watt, 10 amp DC motor? The PWM logic will be created using my Raspberry Pi and an NPN transistor to flip a Solid State Relay rated for the proper voltage and current of the motor. It's my understanding that the rectified voltage will still oscillate up and down, but I am planning on sticking a 250v 1000uF capacitor in parallel with the voltage coming off the rectifier, as well as a flywheel diode across the motor leads. Will that PWM signal be enough to create a moderately smooth motor speed? I am using python on the Raspberry Pi to change the frequency and duty cycle of the logic. I have a program to increase/decrease motor speed from user input on the Pi. Anyhow, I hope this isn't too involved of a question for the comment section. I love your videos, so many of them have helped me. Thanks so much Afrotechmods!
There is another Circuit that I found that uses a Pulsed Signal at 9 to 12 volts Via the 555 Timer to Technically increase the MCD (MilliCandela) on the LED. It pulses it in such a way so it cant overheat the LED Which allows more Current Going to it.
If my 24v dc motor power supply is two 12v batteries in series can I just use power from one of the 12v batteries to run the 555 circuit or should I use the 12v to run an LM317 and then run the circuit from the LM317? Thank you and great video!
Thanks for the great video. I have seen PWM commonly used for electric actuator motors they get 24V AC common and 0-10 dc analog input so how analog input changes the speed of the motor that is already using 24 V AC current what kind of control they use? Thanks in advance
@Aviator14 I think the advantage of this is that with the rheostat, you're generating heat because the extra voltage goes through a resistor, instead of not being used at all like in the PWM circuit. Someone correct me if I'm wrong :)
Hello! Awesome video! I dont understand why I cant just use the potentiometer to regulate the speed of the motor? Why do I need all this circuit to control it?
Afrotechmods Also, even for low amp loads, the amperage output decreases exponentially resulting in a loss of torque (with motors) only using a pot. I've found PWMs keep the amps out relatively the same (as well as torque) regardless of the load up to a point.
This might sound like a dumb question, but if I put a capacitor in series with the output pin line, would i get a straight DC voltage based on the duty cycle (For example, If I feed a 5V PWM signal with a 50% duty cycle, would I get a straight 2.5v DC supply with a capacitor?)
So if you can control the speed of a motor using pwm, how would you control the direction the motor is rotating? Would I need to use an h-bridge for that
Hi Afrotechmod, for dimming LED; is using a thyristor also possible. What are the difference dimming LED with PWM and a thyristor? which is better. Can a thyristor also control motor like the one in your video?Thanks for your reply.
Great vid, i am planning to make a electric go kart this summer and i was wondering if this circuit would work? and is there a way to get a transister to handle that many watts? Thanks.
Never mind turns out it does work I got a big n-channel MOSFET that can handle about 5 to 12 amps with a small fan and heatsink to control the speed of a homemade trolling motor
great video! :) i just have some questions, i have accomplished similar effects for light dimming and motor speed control (in my case i used it as a cpu fan controller) by using lm317 voltage regulator and a potentiometer. so here's the question, what would be the advantage of using PWM over plain voltage regulation using lm317?
I sent this question to your inbox as I dont know in which way you frequently check your followers. I just need more info in case of using the DAQ usb-6008 via its analog output channel. I mean for controlling the duty cycle where I input the analog output of the DAQ in the schematic you provided and the further modifications if needed for the provided schematic connections ? Thanks in advance
Hi...and congrats for those pro videos...i learned a lot..but i have a question?? when you module the width of the pulse...its the amplitude changing too?? or it remains constant.??...all this is because i made a PWM with a 555 from a tutorial...and when i module the width..the amplitude changes too??...but here it remains constant(or maybe you module the oscilloscope too)..please explain this :-)...i will share this with students of an university here in Peru .-)
This is an awesome Tut. i have to use the same Technic like you for the motor. One thing is that i have to use a pic : 18f4550 Do you have a tut for that ? Because i'm very new to Pic programming.
actually any frequencies works to turns the led on and off. but if you mean for convenience to human eyes, any frequencies above 200 Hz usually works fine.
The source power and ground is really confusing me. From the research I've done, it makes it seem like this chip operates on positive voltage only, ie current being drawn away from it. No circuitry I have seen demonstrates current returning into the circuit, by this fact it shouldn't work, but obviously it does. Is ground substituted with negative voltage? or is the negative terminal connected to the ground cables?
SO AFROMAN, this combined with a mosfet or op amp or some amplifier can get me a much higher power PWM wave, hopefully if it has a high enough switching frequency. Now since you're talking about this switching power supplies, what happens if I put an inductor and a diode? Then feed that output into the input, so it can keep it correct. So I can make a switching power supply with ARDUINO??????
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You sir make the best electronics tutorials on the internet! Don't ever stop!
Very nice and clear presentation. Thank you very much. One good presentation is much more efficient for a beginner than reading 10 pages of silly text, and gives appetite for further helpful reading if needed.
Trust me I have been reading about PWM. For quite a bit for now. Nothing is as perfect as this video. The content the narration just perfect.
Why can't all tutorials be like this? Expanding slightly on the circuit construction would be the only added benefit here I can see. Kudos +Afrotechmods
Such simple straightforward explanation! So easy to brush up long forgotten knowledge! Thank you!!!
I built a PWM circuit using your diagram to control current flowing through a non-inductive piece of nichrome wire. Works like a charm. I picked a TIP141 NPN Power Transistor. Before using the 555 I tested it with a function generator and discovered the optimal switching frequency for PWM was about 1khz (close to what you have). In the datasheet TIP141 lists switch on time as 0.9μs and switch off as 11μs. I figured that by adding the values I'd get a full cycle of 11.9μs and a bandwidth cap of 84Khz, yet when cranking up the function generator, I found the real bottleneck to be closer to 8Khz. Pass that TIP141 wasn't able to keep up.
Am I calculating the full cycle wrong is the discrepancy caused by the fact my test conditions (load and base-emitter voltage) being different from those in the TIP141 datasheet?
I'm getting started on electronics and find this one of the best channels on the subject. Also good humor and excellent voice talent.
@blacklust007 Excellent question. The LM317 is a linear voltage regulator which is inherently inefficient. It burns up excess voltage as heat to get the output voltage you want. Power loss will be (Vin - Vout) * Iout. PWM is switching between fully off and fully on, so it will be much more efficient and generate less heat.
Thank you!!! The difference between using a voltage regulator or potentiometer and a pulse width modulator really cleared a lot of things.
@nonodalloo The main thing that will determine the current limit is the transistor you use. You should try find a low resistance N channel MOSFET, put a heatsink on it, and get a schottky diode rated for 5A to put in antiparallel with the motor.
thank you, i have a new knowledge after 10 year you upload this video on youtube
BEST VID EVER really i think it should be featured just because it is so awesomely professional
It's awesome. I heard PWM many time but after watching this video I know that fully.
Thanks a lot.
When you noticed that this video was uploaded about 10 years ago 😂😂 but is more useful than the new ones around
You set new standards in clear communications. Stunningly good video. Thank you friend.
@jwhill15 Sure. Use a separate power supply for the 555, (roughly 10V will do) and then 24V will go on the high side of the motor. Make sure the grounds are all connected.
The PWM output goes though an inductor to a capacitor to filter the waveform into DC. Usually there is a Zener diode to clamp the voltage, but the efficiency is still really good at 80 - 90 percent. Look up the LT3505 chip for a typical example.
You are the god of electronics , I simply am so attracted to the way you teach, that I would like to be your disciple for life. Thanks for the video that is to the point.
Awesome video. I already knew a fair amount about PWM and controlling it, but I needed something simple (ie a 555 circuit) for a single direction, single motor project, and this will work perfectly. Thanks much!
Yup. There's also loads of prebuilt motor controller solutions out there. Just search for motor speed controller. Also, check out Robot Marketplace.
Hey, very good explanation and good images..
one can with good benefits replace the NPN Bipolar Transistor that you show on the image with a mosfet..
some of the main benefits are.
Eliminate the input resistor (known as a base resistor on a BJT)
Allowed faster switching speeds.
Lower on resistance
In most cases cheaper
Lower risk of thermal runaway (due to the thermal behaviour of a Mosfet)
Note that it is not possible to have a 0 to 100% duty cycle with only a 555.
@spelunkerd If you energize a coil like in a motor, what happens is, you establish a magnetic field across it. When the power pulse goes away, the field collapses back across the windings, inducing a voltage back across the coil. Depending the value of that coil, it can be a fairly high voltage. That voltage can destroy your transistor or FET so the diode blocks such voltage and sends it back to the coil to be dissipated instead of across your transistor. This effect is called "back EMF".
hey...thanks for the video......very rarely do i find such a well explained video on youtube....cheers!
I tried this with a TLC555 and nope doesn't work! I kept trying and couldn't get it. So finally I ordered an NE555 and sure enough! it went from 0.2% to 99.9%! Lol, I guess you weren't kidding when you said it won't work will an TLC555. I'am gonna use this on my DIY electric go kart. Thanks Afrotechmods!
Talk about short and sweet. This helped. Great video. Thanks for the upload.
@spelunkerd Also what the diode does is help eliminate what are called eddy currents. Eddy currents flow any direction within a magnetic medium. These fields will collide with and interupt the fields that the control source feeds into it. At these areas of colision, heat is generated, and sometimes, lots of heat. Designers of motors and transformers design spacific shapes and other things into the magnetic medium, to eliminate eddy currents, thus reducing heat buildup.
@Afrotechmods nice job educating people . Keep it up!!
Simplified, professionally done explanation. Thank you sir.
thank you. it was so comprehensive and fast!(Which is a good thing!)
where can I learn more and deeper about this topic?
ok, this make's more logic to me. I am fighting with a pwm circuit now for 2 months, and all burned out. So now i will try this circuit, it looks more solid to me.
Your demo and voice are magnificent, thank you for interpretation.
Change C1 to a lower value to raise the frequency. I'm not sure what the lower bound of the cap value is though. Any frequency above 20Khz or so will be inaudible. If you were using this circuit to control a motor, you could set the switching speed to something like 25Khz and you wouldn't hear a "switching whine."
Wow!! Great.....this is like a way to make the people to get understand. Thank you....
wow, thats great! i understand a lot more if your were the instructor of our technical school. thanks Sir!
Thank you for the wonderful video about PWM. Could you please explain to me what's the purpose of the 10nF caps on the 555 timer pins 2 and 5? Thanks!
@tjnlsn255 Both ways will work. But I would use the LM317 method because a stable voltage over time will mean the frequency and duty cycle won't drift as the batteries discharge.
Good video, thanks. Sorry for being a little dim. How does a diode in parallel with a motor prevent the motor from overheating?
This capacitor shorts out the inductive spike created by the motor starting or stopping. This spike could damage other circuitry. Notice that the diode should be reversed biased to the power applied to the motor. The inductive kick of the motor is of opposite polarity and therefore is dissipated through the diode! It's been a while for me in circuit building but this same principle is used with relays and was used extensively in the stepping relay in the old 8 track tape decks. I hope this helps!
I meant diode, not capacitor. Sorry!
Thank you so much. Very easy to understand what the PWM is!
@Landotter1 What you will need to add is a biasing resistor to the drain of each of the FETs or the emitter of the bipolar transistors. This resistor should be roughly .1 - .5 ohm 5 - 10 Watts. Radio Trash used to sell them but I don't know, these days. Any hifi repair shop will stock them too. Any blown up power amp will have them. In the hifi world, they are called "emitter resistors"
Can you describe how the frequency of the PWM effects the load and how I should choose what freq I want to use ? or suggest another article ?
thank you. cool stuff. it was of particular utility for you to mention that it works up to ~15v. that pre-empted my question concerning whether this would be safe to use with an SLA such as in a car, where it could be up to13.6v or so.
How about doing a part 2 vid on basics on feedback so when heavy loads are applied, the duty cycle will increase to a set value and change back to low load value and no baby sitting. Think a 556 timer will do that right? I forgot...
Thank You for the very good explanation of PWM.
Fantastic tutorial! very clearly explained, but a few questions; how many led's could you control using this PWM? (Im looking at controlling a large array of leds) Also, could this pwm control a 12v motor without any troubles?
in your video you have the 555 timer and the led's being powered by the same 12v source. When you Modulated that into a lower voltage signel wouldn't that also lower the voltage feeding the 555 timer.
Wow I just learned something lol. That actually made a lot of sense. I have a question, do lift switch dimmers use PWM too? Is this why CFL bulbs tend to flicker? If so, would using multiple step down transformers (though impractical) to lower the voltage make a CFL bulb dimmer without flicker?
OMG THIS IS MUCH MUCH EASY TO UNDERSTAND :)))))
compare to my lecturer who yelled at us :" GO BACK TO PRIMARY SCHOOL IF U DONT UNDERSTAND WHAT I'M TALKING!!"
:D
@Afrotechmods Thanks for that well explained answer :) is this the same method used for the PWM fan control system used by current computer motherboards?
It's a quite old electronics video when it mentions Radioshack
Thanks for the video. I love the circuit diagram !
It´s good, but Can you put the circuit diagram or another link to watch it please?
Really thank you. Just I got a trouble With the resistence bulbs, we see an annoying flicker.
@Afrotechmods So technically, there is no limit to the amount of Voltage & Current one can PWM with the 555 timer IC, as long as your electronic components are electrically capable on the high side of the motor? Then in that case you would switch it "on" & "off" (like your transistor video) or using an IGBT (Insulated-Gate Bipolar Transistors) [Which btw, some can even go as high as a rated current of 1,200A & a maximum voltage of 3,300V] or a relay for heavier loads. :)
Great tutorial, wait, did you get that motor from VCR player?
Awesome video!!! I have been searching the web to see if I can get an answer to this question:
If I connect 120v AC mains through a transformer with a 1:1 wind ratio, then through a full wave rectifier, can I PWM the resulting voltage to control the speed of a 1200 watt, 10 amp DC motor? The PWM logic will be created using my Raspberry Pi and an NPN transistor to flip a Solid State Relay rated for the proper voltage and current of the motor. It's my understanding that the rectified voltage will still oscillate up and down, but I am planning on sticking a 250v 1000uF capacitor in parallel with the voltage coming off the rectifier, as well as a flywheel diode across the motor leads. Will that PWM signal be enough to create a moderately smooth motor speed?
I am using python on the Raspberry Pi to change the frequency and duty cycle of the logic. I have a program to increase/decrease motor speed from user input on the Pi.
Anyhow, I hope this isn't too involved of a question for the comment section.
I love your videos, so many of them have helped me. Thanks so much Afrotechmods!
Sounds like you are attempting to regulate the speed of a 90VDC/18amp treadmill motor. Not an easy task.
There is another Circuit that I found that uses a Pulsed Signal at 9 to 12 volts Via the 555 Timer to Technically increase the MCD (MilliCandela) on the LED. It pulses it in such a way so it cant overheat the LED Which allows more Current Going to it.
Awesome vid. Thanks for sharing your valuable time and knowledge.
much better explanation than my lecturer
If my 24v dc motor power supply is two 12v batteries in series can I just use power from one of the 12v batteries to run the 555 circuit or should I use the 12v to run an LM317 and then run the circuit from the LM317?
Thank you and great video!
Working on one right now!
This was a fantastically informational. Thank you
Thanks for the great video. I have seen PWM commonly used for electric actuator motors they get 24V AC common and 0-10 dc analog input so how analog input changes the speed of the motor that is already using 24 V AC current what kind of control they use? Thanks in advance
@Aviator14 I think the advantage of this is that with the rheostat, you're generating heat because the extra voltage goes through a resistor, instead of not being used at all like in the PWM circuit. Someone correct me if I'm wrong :)
Hello! Awesome video! I dont understand why I cant just use the potentiometer to regulate the speed of the motor? Why do I need all this circuit to control it?
You can, but this is much more efficient
Afrotechmods Also, even for low amp loads, the amperage output decreases exponentially resulting in a loss of torque (with motors) only using a pot. I've found PWMs keep the amps out relatively the same (as well as torque) regardless of the load up to a point.
the radioshack near me closed :(
I get all my stuff on either amazon or direct from China if it is bulk components.
This might sound like a dumb question, but if I put a capacitor in series with the output pin line, would i get a straight DC voltage based on the duty cycle (For example, If I feed a 5V PWM signal with a 50% duty cycle, would I get a straight 2.5v DC supply with a capacitor?)
Great video fellow VAIO user. Thanks for the tutorial.
I like this video, well done and explained.
Very concise and informative. Thank you!
Why not just use a potentiometer to adjust voltage? What is the benefit of making a squarewave and adjusting the PWM?
So if you can control the speed of a motor using pwm, how would you control the direction the motor is rotating? Would I need to use an h-bridge for that
yes h bridge is used to change direction of motor bcoz it changes polarity very very fast
Succinct, descriptive, excellent.
@Afrotechmods would you do a simple communication application of PWM? thanks!
i love your video style!
Hi Afrotechmod,
for dimming LED; is using a thyristor also possible. What are the difference dimming LED with PWM and a thyristor? which is better. Can a thyristor also control motor like the one in your video?Thanks for your reply.
Great vid, i am planning to make a electric go kart this summer and i was wondering if this circuit would work? and is there a way to get a transister to handle that many watts? Thanks.
Never mind turns out it does work I got a big n-channel MOSFET that can handle about 5 to 12 amps with a small fan and heatsink to control the speed of a homemade trolling motor
great video! :) i just have some questions, i have accomplished similar effects for light dimming and motor speed control (in my case i used it as a cpu fan controller) by using lm317 voltage regulator and a potentiometer. so here's the question, what would be the advantage of using PWM over plain voltage regulation using lm317?
The potentiometer will heat up even at slight loads. On the other hand, by heating, it consumes power = not efficient.
nice video thanks for the upload. Could you do a video on AC PWM for a motor?
I sent this question to your inbox as I dont know in which way you frequently check your followers.
I just need more info in case of using the DAQ usb-6008 via its analog output channel. I mean for controlling the duty cycle where I input the analog output of the DAQ in the schematic you provided and the further modifications if needed for the provided schematic connections ?
Thanks in advance
Nice, clear and concise. Thanks
Huh! I haven't seen that 555 astable multivibrator configuration before. Definitely gonna write that down.
Hi...and congrats for those pro videos...i learned a lot..but i have a question?? when you module the width of the pulse...its the amplitude changing too?? or it remains constant.??...all this is because i made a PWM with a 555 from a tutorial...and when i module the width..the amplitude changes too??...but here it remains constant(or maybe you module the oscilloscope too)..please explain this :-)...i will share this with students of an university here in Peru .-)
The amplitude should stay the same - it should be the same as what the power supply is. There may be small spikes during the transitions though.
i knew it..friends told me the other....thnx a lot for it...i'll research and prove it to them thnx a lot (Y) :D
is this circuit also used in switching power supplies?
I wish to make a capacitor charger using this technique in a switching inverter
This is an awesome Tut. i have to use the same Technic like you for the motor. One thing is that i have to use a pic : 18f4550 Do you have a tut for that ? Because i'm very new to Pic programming.
short durantion and very helpful... awesome.
you should definitely write a book with electronic experiences and link it to your videos on youtube to understand electronic concepts.
Thanks for the video. Do you know how we could change the shape of the pulse waveforms, especially in pemf device circuit?
very nice! now you should make a video on how to generate pwm through software :)
i understand the point that pwm can control speed of motors since signals turn on and off. but how it works on an led?
on an led, pwm turns the led on and off too.
+Radius Indrawan but is the frequency of PWM for led more than that for motor?
actually any frequencies works to turns the led on and off. but if you mean for convenience to human eyes, any frequencies above 200 Hz usually works fine.
And this circuit is about 1.2 Khz
Should i use a MOSFET or transistor. I saw many people use MOSFETs instead of transistors
The source power and ground is really confusing me.
From the research I've done, it makes it seem like this chip operates on positive voltage only, ie current being drawn away from it.
No circuitry I have seen demonstrates current returning into the circuit, by this fact it shouldn't work, but obviously it does.
Is ground substituted with negative voltage?
or is the negative terminal connected to the ground cables?
SO AFROMAN, this combined with a mosfet or op amp or some amplifier can get me a much higher power PWM wave, hopefully if it has a high enough switching frequency. Now since you're talking about this switching power supplies, what happens if I put an inductor and a diode? Then feed that output into the input, so it can keep it correct. So I can make a switching power supply with ARDUINO??????
this circuit works well with TIP120 at 4.5 volts, as you said
Thank u for explaining in detailed manner
Perfect explanation. Thank you!
Thank you, Afroman! That explains a lot!
Cheers!
What if I want to have a pulse with 1.5T? Would I need capacitors or how would the circuit change?
Are there multiple standards for identifying ceramic caps? I have found some that have both numbers and letters.