modified 10 years ago

Peak hold audio indicator

01:03:18

Different topology. The last one was not very well thought out.

published 11 years ago

hurz

11 years ago

Unfortunately the 10k is grounded by the DC source, so no feedback at all possible. Your source needs an internal resistance so the feedback can work against it. If you dont belive just remove the 10k and see the circuit behavior does not change. Some time ago I have publish a circuit to explain the problem (which I found many times here on EC circuits) search for "input impedance problem". Hope this helps.

zorgrian

11 years ago

Okay I see your point. Remove the 10 k resistor and we get the same functionality. So what do you suggest? 500 ohm resistor in series with the signal generator didn't help too much.

zorgrian

11 years ago

Okay so I put a 1K resistor in series with the signal generator and another in the feedback to the base. This is far from ideal. What is a better solution? This is horrible!

hurz

11 years ago

What is the exact target you want?

zorgrian

11 years ago

Actually, I just want a simple peak audio LED indicator. I could probably use some hysteresis so the peaks show on the LED for a few milliseconds. I also wanted to use a self biasing configuration because I think they are neat.

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