Pyrography tool, PWM from 555 timer. Please help!

Thread Starter

Will_s87

Joined Dec 27, 2014
2
Hello

I built this circuit today, its a pyrography tool for burning wood, to make pictures, decorating etc...
I have connected the nichrome wire (toaster wire at the moment for testing) as shown in the diagram

When I switch on, the toaster wire glows nicely providing you cut it at the right length, unfortunately when I adjust the pot I get no obvious change in heat output on the toaster wire,
I dont have any understanding of electronics, only a simple grasp of electricity, so go easy please :)
I have checked all my part numbers and connections a few times, I have also swapped the timer and transistor for new ones incase I burnt them while soldering,

Can anyone offer some advise where to start troubleshooting, I have only a basic DMM
(my diode is the right way round, and I definately have the wiper connected to pin 7)

thanks :)
Will


 

Colin55

Joined Aug 27, 2015
519
What you do is get an alligator clip and move it along the wire until the wire is the right temp. Remove all the electronics and just put the wire between the 5v and COM
 

Thread Starter

Will_s87

Joined Dec 27, 2014
2
Ill try swapping the drain and source over when I get home from work. Thanks,
Any suggestions for a better circuit design?
Would any 555 timer used to make a PWM for transistor work /
 
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