This low noise microphone preamplifier circuit was found in American documentation from the 90s. The circuit requires special care with the layout. The power can be between 9 and 18 V.
We can obtain the voltage multiplication using all six inverters of a 4049 integrated circuit, as...
The existence of field effect transistors at the input of the integrated circuit (operational...
This circuit can be adapted to an FM radio or other receiver that does not have a tuning indicator LED....