View Full Version : problem with pwm using 555

02-29-2012, 12:10 PM
I just wanted to make my first toy car....So i wanted to use a pwm to controll the speed,and to turn left,right.


This is the circuit which i was referring for making my car as i feel that its the most easiest ckt bcos of its components.

The problem i found was that the discharge pin (7) was left open....I knew that discharge pin is used to discharge the inbuilt capacitor,in this case it is left open.May i know how to make it complete.

And one more dbt....

I have the transistor BC 547 instead of TIP 31,Will the transistor be compatible with the ckt....i found that the collector current of bc 547 is 100mA,for TIP 31 it is 3A.

03-21-2012, 10:32 PM
as far as i know, you can connect the discharge pin to the capacitor and then to the ground

03-22-2012, 04:54 PM
Hi.. You cannot use BC547. It would not supply enough current to your motors. Its better if you use 187.