Hi guys
I made an ultrasonic atomizer circuit using TIP41C as attached. The circuit works fine when I am using single atomizer (unite 1). But when I attached another (the same) unit to rectifier bridge right after 47uF capacitor, one of the units' transistor will burn after a while. The other transistor can work for very long time without any problem. Can you please help me to find how to parallel several units to one bridge?
Ps, the rectifire bridge is 10A, and the circuit draw about 0.7A from transformer primery (220v) side.

 

Sounds like they need filtering seperately with diodes and inductors to stop oscillations beating against on another.

 

I would tend to agree with Dodgydave, the simplest solution that might work would be to supply each unit’s d.c. voltage via a diode (1N4002 to 1N4007), which should stop any electrical noise in one circuit reaching another.

I would recommend you provide each separated d.c. voltage with its own reservoir capacitor of at least 47uF. Drawing 0.7A on a rectifier output held up by a 47uF will result in a large rail ripple voltage, I’d recommend you increase the capacitor value by a factor of 10.

The increased rail ripple voltage due to adding extra units might be at the root of the issue.

 

Thank you all, I will try to put a diode and see the results.