Accurate Bass Tone Control

A difficult problem in the design of conventional stereo tone controls is obtaining synchronous travel of the potentiometers. Even a slight error in synchrony can cause phase and amplitude differences between the two channels. Moreover, linear potentiometers are often used Continue reading

Amplified Ear

Amplified Ear Circuit Description This circuit, connected to 32 Ohm impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard. You can also listen to your television set at a Continue reading

Hearing Aid

Hearing Aid Description Commercially available hearing aids are quite costly. Here is an inexpensive hearing aid circuit that uses just four transistors and a few passive components. Circuit diagram Parts: R1 = 2.2K R2 = 680K R3 = 3.3k R4 Continue reading

A Low Cost Hearing Aid

A Low Cost Hearing Aid Circuit Description This low-cost, general-purpose electronic hearing aid works off 3V DC (2×1.5V battery). The circuit can be easily assembled on a veroboard. For easy assembling and maintenance, use an 8-pin DIP IC socket for Continue reading