Dear everyone,

I have a design of 38KHz generator for IR source. The problem is practical value differs lot from theoretical. I know the resistance tolerance will affect the output and also i want to know if any other parameter affects the frequency. Please give your advice.

 

Hello,

Can you post a schematic?
The capacitor in the timing circuit may have a large tolerance.

Bertus

 

At 38 k Hz, timing cap is small & film type, relativley stable. Tolerance not a problem because timing R is part pot. The IR receivers I've tried had broad tuning, several k Hz wide.

 

Based on the information supplied, the frequency will vary from between zero and infinity.

Post schematic and parts list for a real answer... but don't expect anyone to actually search out the specs of all the parts. That's your job.

We can point you in the direction. We're not going to do your grunt work for you.

 

I would use a 555 circuit, but it is probably not as stable as you probably want. This is a situation where more information is needed.