This circuit is from American documentation from the 1980s. The circuit can make use of any common NPN transistor and the power comes from two small batteries.
Found in a 90s Hands On Electronics, this small preamp finds applications like microphones and other...
This bridge audio amplifier was found in the July 1984 issue of Radio Electronics magazine. The...
The CUT frequency for this filter is determined by the capacitors. The µA4138 is a quad version of...