How to control the motor speed in 555 timer pwm?

[faraz101]

i have build 555 timer pwm circuit and i am varying the motor speed with the variblre resistor b/w pin 7 and 6.but i want to control the speed form external analog voltages which ranges form 0.80v to 1.20v.
any ideas
thanx

 

[A.Anand Srinivasan]

pwm 555

the control pin5 can be used but a amplified version of the 0.8 to 1.2V signal would be needed as far as i know....

 

[faraz101]

555 timer pwm circuit

i already work on it but it is not giving a wide speed range.coz pin5 already have some voltage about 3v.
thanx 4 reply

 

[ultrabrains]

555 pwm

you can connect a resistor to ground to reduce the voltage on pin5 .

i worked on it a long time ago and i used a transistor circuit to pull th evoltage at pin5 to ground and it did work well

cheers

 

[A.Anand Srinivasan]

555 pwm circuit

pin5 will have a voltage because it is part of a internal voltage divider.... it can be varied externally according to our need....

 

[yogi]

pwm with 555

if you are using potentiomenter, then you require just one potentiometer and a diode with 555 astable multivibrator circuit
http://www.geocities.com/njbibin/robo14.html

Bibin John
www.bibinjohn.tk