This amplifier with gain control was obtained in a documentation from Signetics of the 80's. Transistors are of power and operational amplifiers are not common nowadays.
This traditional version of astable signaling transistors was found in an American 1980s...
This circuit was obtained from English documentation on FETs. The JFET can be any general purpose and...
This circuit is from an old publication from the 1950s. The circuit uses germanium transistors but can be...