In the attached schematic, which I found on-line as part of a preamp for an electret mic, I found that the circuit loaded the input source excessively. Using the component values shown, my input signal went from .6 Vpp (no load) to .01 Vpp, and the output from the circuit was only .08 Vpp. I changed R1 to 1 MΩ and R2 to 10 MΩ, which allowed the input to be .42 Vpp and the output was 4.3 Vpp. This was more what I was looking for.
My questions are:
1. Would an electret mic (which I didn't use as an input device) have been loaded less than my sine wave oscillator (which is a simple LM741 circuit.)
2. Is there any reason why the input resistor should be 4.7k? Is there ever a case when a low value like this is needed?
3. Is there anything wrong with using megohm range values for R1 and R2?
And an unrelated question:
4. How does one choose the values for C1 and C2?
Thanks.
My questions are:
1. Would an electret mic (which I didn't use as an input device) have been loaded less than my sine wave oscillator (which is a simple LM741 circuit.)
2. Is there any reason why the input resistor should be 4.7k? Is there ever a case when a low value like this is needed?
3. Is there anything wrong with using megohm range values for R1 and R2?
And an unrelated question:
4. How does one choose the values for C1 and C2?
Thanks.
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