This is simply a direct phone line not an intercom but meh! so i can speak and hear at the same time.
so I'm using the switch in the base and the electret mic and speaker in the head set (chucking the pcb). im going to be using a buzzer i buy and the dpdt switch in the base to switch the buzzer on and off but i dont know how to amplify the signal from the electret mic. i know they need power (my electret mic has 2 solder tabs) but the resistor and capacitor sizes seem to vary so much (is there a calculation involved). I have lm741 opamps, can i use them??
thanks for any help!