We found this preamplifier with 70 dB gain for microphones in American documentation from the 90's. Consumption is low and equivalent transistors can be used.
Found in a 1990 Hobbyst Handbook this circuit has an output power of a few tens of watts and...
Two NAND gates are used in the configuration shown here to perform as a monostable triggered by...
Found in a 1980s American documentation, this circuit is based on the common CMOS series...