This circuit is from a 90s documentation. It has a hysteresis and uses a light sensing bridge. The circuit generates a 1000 Hz modulated 10 Hz signal. The signal must be applied to an amplifier.
The circuit whose characteristics are given in the graph uses two transconductance operational amplifiers...
This circuit was found in the Radio Electronics magazine in an article about emitter-coupled...
This circuit was obtained from an 80s factory manual. The integrated circuits used are uncommon...