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.
This circuit of the 80's makes use of components of the time. The circuit is from an American...
This circuit was found in 1966 General Electric documentation. The circuit uses components from the era...
E) This audio filter was found in the August 1993 issue of Radio Electronics magazine. It cuts low...