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Sine wave signal generator

N

Napalm Llama

Jan 1, 1970
0
Hi. I've been tinkering with the odd electronics project for a few
years now, but I'm stumped on this one. I've constructed this circuit:

http://www.yellowmackerel.co.uk/circuit.gif
(Originally from here: http://www.4qdtec.com/singen.html , but the
server seems to be down.)

....except I'm using an NE5534AP op-amp instead of the 6-transitor
circuit (as the accompanying text said I could).

But it isn't working. All I get is a low tone that sounds suspiciously
like 50Hz. I've checked the power supply circuit with my multimeter
and the output seems to be perfect, but I can't check how much ripple
there is because I don't have an oscilloscope.

The dual-ganged potentiometer seems to alter the volume instead of the
tone, and the rotary switch doesn't really do much at all. The op-amp
itself just gets worryingly hot.

I've just discovered that if I only connect 0v to the IC and put my
thumb across the "lower" pot in the circuit, moving it does alter the
tone a little.

I don't know if this is enough to go on, but please help in any way you
can - I've spent a fair bit of money on this project and I don't know
why it isn't working...
 
D

Dan H

Jan 1, 1970
0
Napalm said:
Hi. I've been tinkering with the odd electronics project for a few
years now, but I'm stumped on this one. I've constructed this circuit:

http://www.yellowmackerel.co.uk/circuit.gif
(Originally from here: http://www.4qdtec.com/singen.html , but the
server seems to be down.)

...except I'm using an NE5534AP op-amp instead of the 6-transitor
circuit (as the accompanying text said I could).

But it isn't working. All I get is a low tone that sounds suspiciously
like 50Hz. I've checked the power supply circuit with my multimeter
and the output seems to be perfect, but I can't check how much ripple
there is because I don't have an oscilloscope.

The dual-ganged potentiometer seems to alter the volume instead of the
tone, and the rotary switch doesn't really do much at all. The op-amp
itself just gets worryingly hot.


You need to show the actual circuit you are using not the circuit you
have based it on

dan
 
T

Tom Lloyd

Jan 1, 1970
0
Hmm, perhaps a better question to ask would be, "How should I actually
substitute an NE3455AP (http://www.ampslab.com/PDF/ne5534p.pdf) into
the circuit I posted?
From the original webpage:
"The 6 transistor circuit is, in effect, an op-amp and there is no reason you can't simply use an op-amp. This circuit pre-dates op-amps but the principles haven't changed."

It's all obvious, except for the inputs - there appears to be only one
in the schematic (at the base of the leftmost transistor). I tried
wiring that up to my op-amp on pin 2 (inverting input) - and then 0v on
pin3 (non-inverting) - but like I said, it didn't do anything except
get hot.
 
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