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Electronics => Electronics => Topic started by: aruna1 on April 12, 2010, 04:11:47 AM

Title: transistor based pwm generator
Post by: aruna1 on April 12, 2010, 04:11:47 AM
Hi guys I need a small PWM generator circuit to control brightness of two LEDs. well I'm looking for a transistor based circuit.any ideas? (i want to make it smaller thats why i didnt choose 555 timer)
thanks
Title: Re: transistor based pwm generator
Post by: billhowl on April 12, 2010, 07:20:23 AM
http://en.wikipedia.org/wiki/Multivibrator (http://en.wikipedia.org/wiki/Multivibrator)

C1, C2 = 0.0022uF
R1, R4 = 1 K Ohms
R2, R3 = 10K Ohms
R5 = 2M Ohms

Title: Re: transistor based pwm generator
Post by: aruna1 on April 12, 2010, 08:19:43 PM
http://en.wikipedia.org/wiki/Multivibrator (http://en.wikipedia.org/wiki/Multivibrator)

C1, C2 = 0.0022uF
R1, R4 = 1 K Ohms
R2, R3 = 10K Ohms
R5 = 2M Ohms



hi i think
C1, C2 = 0.1uF
R1, R4 = 1 K Ohms
R2, R3 = 10K Ohms
R5 = 100k Ohms

is more suitable.it gives better pwm shape.
see the simulation result