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.
This circuit consists of a simple capacitance bridge. The handset can be high impedance from 500...
This simple wireless microphone circuit for the MW band was found in an old American...
This astable with active cycle adjustment was found in a Popular Electronics from the 90's. The...