The integrated circuit used in this 1975 application no longer exists, and it is also not indicated in the original diagram and must be of the TAA series by the diagram.
We found this circuit in a Popular Electronics of the 90s. The MOSFET can be of any type,...
In fact, the correct name would be a hearing aid amplifier. However, we use the name of the...
This circuit controls a relay causing it to open and close its contacts at a speed that depends on the...