This simple circuit has good gain and can be implemented with any general-purpose transistor. The circuit is from Electronics Now, June 1997. The coil determines the frequency range.
) The integrated circuit used is uncommon today. The circuit is suggested by Motorola's Linear...
This low-pass filter with 741 op and symmetrical source was found in the August 1993 issue of...
This receiver for listening to headphones and 2-battery power was found in Japanese documentation from the...