**broken link removed**
Hey guys,
I am using a condenser microphone to pick-up sound pulses, and then input them in the form of very low voltage (micro-volt) signals into an LM741 op-amp to amplify them.
The problem is, the sound I am picking up (beep pulses) is not being amplified enough through the op-amp enough to saturate the transistor to .7 volts. What I am getting now, Vout is about MAX 100milli-volts.
As far as I know I should increase the Gain, but I am already using a 10M Ohm resistor as Rf, and a 1k Ohm resistor as Rin, therefore, technically the gain is around 10000 which doesn't make sense, but it is working better than the 200K (Rf) and 1k (Ri) which equaled a gain of 200.
Any ideas how I could boost the output of the condenser mic to much greater than .7 volts maybe at least .8 to 1 volt preferably.
BTW, the components are a little hard to see so here is a list:
*The box with the black X on it is the condenser mic.
*Rf = 10M Ohm, Ri = 1K Ohm
*The two resistors forming the voltage divider are 4.7K Ohm, which inputs 1/2 Vsource = about 5 volts input to non- inv input.
*The caps are .1uF, .01uF, and 1uF, all for de-coupling.
*2222a transistor, but I have available: 3904, 5088, and 4401
*1K Ohm limiting current through the LED in the collector.
*Output of condenser into the inv, input of LM741, with a de-coupling capacitor.
Thanks a lot for your time.
Phill