This circuit uses an HA2400 consisting of 4 digitally controlled operational amplifiers. The circuit is from a Radio Electronics magazine from March 1980. The power supply must be symmetrical.
Found in Mullard's 1960s transistor manual, this circuit has components that depend on the...
This signal injector uses a single integrated circuit as an oscillator, producing rectangular...
This second amplifier is based on the integrated LM108 and has a differential input. The resistor...