This amplifier for hearing aid was found in a 1968 documentation using an integrated of the time. The power is from a battery, the consumption of 1.65 mA and the power of about to 1 mW.
The power supply shown has the circuit shown in the figure, and transformers of 5 + 5, 6 + 6, 7.5...
This sensitive continuity test uses two transistors and has a common LED as indicator. The input...
This circuit was obtained in an American publication of 1977. The circuit generates rectangular...