| Author |
 Topic  |
|
n/a
DELETED (Inactive)
8 Posts |
 Posted - Mar 07 2004 : 9:32:42 PM
|
Does the PWM circuit on this website work?
Thanks
(Edit...Fix useless subject line)
Edited by - Aaron Cake on Mar 08 2004 10:25:04 AM |
|
|
Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Mar 08 2004 : 10:25:41 AM
|
Nope. Doesn't work at all. Sometimes I post broken circuits to keep people on their toes...
|
 |
|
|
n/a
DELETED (Inactive)
8 Posts |
Posted - Mar 11 2004 : 11:02:02 PM
|
Explains why it doesnt work. Great, wasted $30 for parts
|
|
|
|
Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Mar 12 2004 : 09:12:10 AM
|
Um, that was a joke...Yes, the circuit works fine.
|
|
|
|
n/a
DELETED (Inactive)
3 Posts |
Posted - Mar 18 2004 : 06:55:22 AM
|
can u send me the detailed constuction
|
|
|
|
Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Mar 18 2004 : 09:14:25 AM
|
There are no "step by step" instructions available. Standard assembly techniques should be used.
|
|
|
|
n/a
DELETED (Inactive)
8 Posts |
Posted - Mar 20 2004 : 03:40:17 AM
|
If anyone wants to build this PWM and doesnt have a basic background and also lives in Toronto or surrounding areas, you could pick up a PWM kit at A1Parts on Kipling. They actually have it for cheaper than buying everything for around $22. not to mention that there is nothing wrong with the circuit on this site, it works great for me. Just FYI.
|
|
|
|
Presbychuck
Apprentece
USA
5 Posts |
Posted - Dec 01 2006 : 9:03:51 PM
|
I need help with this circuit. I am trying to make a PWM controller to use for some electric motorcycle clothing. ANyway, I assembled the circuit as per the schematic and as a test, hooked it to a 12V light bulb to observe the functionality. What happens is that the lowest pot setting gives me about 60% power and the pot setting makes no difference until about 8 (on a 1-10 scale). Then from 8-10 the power increases to about 80% or so. I have constructed the circuit three times with identical results using all new components each time. I did deter from the schematic when I could not find the listed MOSFETs. I substituted IRF540's instead. Can you help me make this work or at least tell me when to give up? LOL
TIA
chuck |
|
|
|
audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Dec 01 2006 : 11:53:52 PM
|
This circuit is an ordinary Cmos variable frequency oscillator. It doesn't produce Pulse Width Modulation, the pot just changes the frequency. The frequency changing changes the speed a little of some DC motors because their inductance causes them to slow down a little at high frequency. This circuit needs two diodes added and the ends of the pot connected to the diodes so that the duty-cycle of the pulses can be changed. Then Pulse Width Modulation will be produced to control the speed of a DC motor or the brightness of a DC lamp. The fixed circuit is in Don Lancaster's Cmos Cookbook but I couldn't find the circuit on the web.
A 555 oscillator can also produce Pulse Width Modulation if two diodes are added. |
|
|
|
Presbychuck
Apprentece
USA
5 Posts |
Posted - Dec 02 2006 : 12:33:16 PM
|
Thanks guru, that makes some sense even to my small mind. But can you offer me any clues as to WHAT diodes and from whence to insert them? If need be I can fall back on a 555 design I have used in the past, but this circuit, appearing so simple, was easier to wrangle for newbie me. I am trying to make a three channel controller. Since this one is done save this issue, I'd like to make it work. If I need to scrap it and get on with the 555 board, then so be it.
Thanks so much for your time and knowledge.
chuck |
|
|
|
audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Dec 02 2006 : 2:04:41 PM
|
The circuit here uses a 4 gate IC. It has both inputs joined so its input threshold voltage is not symmetrical. Only a single input should be used to make the inputs symmetrical.
A 4069 hex inverter IC will make 3 of these circuits.
The gates or inverters in this circuit operate at only a few mA when they are working hard. herefore any little diode would work. I use 1N914 and 1N4148 for little diodes.
If I could attach my sketch here showing how to connect the required diodes for it to make PWM then I would. |
|
|
|
Presbychuck
Apprentece
USA
5 Posts |
Posted - Dec 02 2006 : 9:08:15 PM
|
Audioguru,
If you could send the sketch to presbychuck at hotmail dot com then I would have it. :) And I do have a few of 1N4148's on hand. Thanks a million. |
|
|
|
audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Dec 02 2006 : 10:14:33 PM
|
| Sorry, no e-mailing. |
|
|
|
Presbychuck
Apprentece
USA
5 Posts |
Posted - Dec 03 2006 : 12:14:58 AM
|
| OK Thanks anyway. I'm going back to a 555 controller. I know how to get that one going. |
|
|
|
Aaron Cake
Administrator
Canada
6718 Posts |
|
|
Presbychuck
Apprentece
USA
5 Posts |
|
|
Topic |
|
PWM Motor Controller
