Testing LFO without Oscilloscope?

[D Wagner]

Hey Guys,

What is the best way to test the function of an LFO without an oscilloscope?

Should I use the output to trigger a transistor and an LED?  

I would welcome any suggestions.

Thanks!

Derek

[Mark Hammer]

You could do that.  Alternatively, you could set it to the slowest speed, and park the probe of an analog voltmeter at its output.  I stress analog because the needle yields a more coherent indicator of cyclical variation than a digital readout.  The advantage of the analog meter over the transistor/LED combo is that you'll know what the output voltage is, approximately.

[gez]

I once tuned a sine wave oscillator using the method Mark outlined (twas a diode shaping affair).  When I finally got a scope I breadboarded the circuit to check it out 'for real' and it was more or less spot on - not bad for a log meter!

To get the LFO slow enough to take a reading I paralleled really large value caps with the one that sets the rate (not always possible to do, depends on the oscillator).