Design and construction of a simple wired two station intercom systems

Abstract

This is a design of a two stationed intercom system for easing communication between two or more rooms/offices within the same building or organisation. The main component of this system is the operational amplifier and this amplifies the incoming sound signals from the microphone at one station and then outputs it via the speaker at the other station. While maintaining the resistance Rf constant, I varied the values of resistance Rin in order to obtain various values of the gain of the operational amplifier. What I found out is that; as the resistance Rin is increased, the gain of the amplifier decreases. This has an implication that; if one wishes to obtain a large amplifier gain, one must use a very low resistance Rin given a large value of resistance Rf