This circuit is from a Popular Electronics from the 90's. The audio amplifier admits equivalent. The others integrated are not very common today.
This amplifier can be powered with voltages from 9 to 14 V providing 7W of maximum power under a 8 ohms...
A flash of light on one sensor or the touch of your fingers on the other type of sensor will turn...
Found in an American publication from 1968, this circuit generates pulses at a rate of 2,500 per...