PWM help needed

Thread Starter

Jacob J

Joined Jun 18, 2009
159
I changed the resistor because SgtWookie said so. I have a now changed the 8,2k to a 1k (that is the only one I have). I have removed the 555 timer, put in a new. I have taken the shorter between 3 and 4 out. It still dont work. I can take my potentiometer out, and the motor still runs at the same speed, wich I think is a bit strange.

The timer is a LM555CN and the transistor is a TIP122.

I just cant figure out, why it isnt working..
 

Wendy

Joined Mar 24, 2008
21,840
Try the LED schem I show in my layout, it will provide feedback if it is working or not. If only one or the other LED is lite then you don't have oscillation.
 

Thread Starter

Jacob J

Joined Jun 18, 2009
159
I have placed my diodes (LED) in the same layout as your drawing shows. I will try to replace both diodes with new ones. But should my motor be running at constant speed, if one of the diodes didnt work?
 

Thread Starter

Jacob J

Joined Jun 18, 2009
159
Now I have tried to put in those leds, but they wont light. Just cant figure out, what I have done wrong. Does my breadboard design look alright except the shorting on 3 and 4 and the big capasitor?
 

Thread Starter

Jacob J

Joined Jun 18, 2009
159
I have found out what the problem was. I had connected my transistor wrong. It works like a charme. Thank you all for your help.
 
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