simple PWM

[bogdan2]

i found this simple PWM for motor control.
it is something usefull, and i was thinking to build it and wanted to know what others think.
maybe some of you know a similar circuit, i mean, simple, but maybe more performant?
here is the circuit:
http://www.geocities.com/tjacodesign/motor/motor.html

 

[Ldanielrosa1]

It doesn't get much simpler. The chip can be a 40106 with minor changes. There is something that uses all discretes at

http://www.romanblack.com/

One downside to these designs is that the frequency is not controlled, and as such may have some annoying side effects. For a motor control this is not likely to be a problem. Another point lacking is that interfacing these to some automatic control will be difficult.

 

[Kevin Weddle]

I built a circuit similar to this and found that my relaxation oscillater did not give me good results. I used a NAND with feedback and a capacitor and resistor. The voltage I got was not stable enough to be considered a clock. This might be interesting to anybody trying to configure a clock circuit.