Dave a écrit :
Building the attached schematic, only I have no signal output on pin 3 of
the 555. My calculations tell me it should be a 10.2 KHz squarewave, but -
nothing. When power is applied, it goes to ground, and I have checked and
rechecked all my connections. Somebody please tell me what I am doing
wrong. I used the same setup for a transistor tester, and it worked fine.
Keep thinking something has failed to make contact with the solder applied
to it, but that doesn't seem to be the trouble. I guess I'm asking if this
*looks* right, cause that would mean I do have a wiring error. Or is there
something here I don't know about the 555? Pin 3 should have a square wave
on it, even if it is not connected to anything but a scope, right?

Thanks,

Dave




Change R1&R2 to 47K and the 1uF cap to 1nF.


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Thanks,
Fred.