Using a 709 integrated circuit this circuit was found in the June 1972 issue of Radio Electronics magazine. More modern operational equivalents can be used. The power supply is symmetrical.
Using the LM380, this circuit provides a power of the order of 200 mW. In it we have a stage of...
I found this circuit in an article in a 2003 publication. The circuit is an example of how to...
We found this circuit in a Radio Electronics from October 1965. The pickup coil can be of the...