Today we have more compact solutions. This is from a Radio Electronics magazine from October 1990. It uses the technology of the time.
Found in a 73 magazine for radio amateurs of the 1980s, this circuit uses a dual-gate MOSFET. This...
This circuit is intended for communications receivers. We can find it in a documentation from the...
This traditional TTL configuration was obtained in a 1977 documentation. The supply must be made...