Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Himanshu on January 27, 2012, 09:43:42 AM
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Hello,
i want to know how to implement pulse width modulation(PWM) on a circuit, what additional components like resistance and capacitor are required.
also i want to know how to implement PWM on 8051 microcontroller.
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I'm thinking about using an LM555 timer IC as a PWM generator. Hook it up in astable mode like this (http://en.wikipedia.org/wiki/555_timer_ic#Astable). Full disclosure: I haven't actually tried it yet. But it should work!
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Circuit below will generate PWM with variable duty cycle. Change Cap or Pot value to get different frequency.
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Hi,
Change Cap or Pot value to get different frequency.
First it needs to be rearranged a bit ;)
As shown, it's possible (likely even) to short pin 7 to Vcc (Not Vdd, it's an analog device), which will kill the internal transistor driving this pin.
I have attached an example of a PWM circuit that works reliably and relates M/S ratio closely to pot-position.