Electronics Q - Simple oscillators

[Narcosynthesis]

I found one of those kits you get for kids '20 electronics projects' and was toying around and found a circuit for 'pencil music' basically an oscillator, and you can control the frequency by moving two wires across a box of scribbled pencil (so thats a variable resister then )

Tried it on the kit and it worked nicely, so though I would build it into a wee box as a fun wee musical toy, but when I tried breadboarding it up it dosen't seem to work, and after trying it on the electronics kit again I can't get that to work either (redone it a couple of times now by the letter)

So, anyone got any very simple wee oscillator schematics I could try? or ideas what could happen? I wouldn't have thought the IC would be suceptable to static or anything, as it is just an op amp, and used in a kit designed for kids but I have tried a couple and none seemed to do anything. the one I have uses and LM324 IC if that makes any difference...

David

[Sir H C]

Simplist oscillator is the phase shife one.  Most often seen for LFOs on amps. 

http://www.visionics.ee/curriculum/Experiments/RC%20Phase%20Shift%20Oscillator/RC%20Phase%20Shift%20Oscillator1.html

By changing some of the resistor values (one often) you can change the frequency.  So set up the pencil stuff as one of the R's in the RC phase shift.

[Narcosynthesis]

I was wandering about my op amp version, Which I can't seem to get working, anyone know of any reasons why it would just stop working? thats following the instructions in the book to the letter or repeating it all on separate breadboard...

David

[RaceDriver205]

Bread boards make it incredibly easy to do a wrong connection. You may have put a wire in the wrong row, or two leads might be touching or something like that.

[Sir H C]

And sometimes breadboards get bad contacts or shorts to the plane in the back.  Either hoses what you are trying to do.

[Narcosynthesis]

I have followed it to the letter on the kit's setup (a breadboard split into wee blocks) and also on my own board, both done multiple times to try and get rid of any odd wires or whatever...

David