With this circuit it is possible to tune an AM signal using a 5k potentiometer (4k7). The circuit was found in a publication from the 1980s and the PLL can be replaced by an equivalent one, with tests.
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...