This circuit was found in a Popular Electronics from the 90s. The transistors are general purpose, and the gain depends on the ratio between R2 and R1.
This detector uses an unusual sensor today. The circuit is from an 80s documentation. Its...
Found in a 90’s Popular Electronics, this circuit applies to almost any operational amplifier. With...
This circuit divides the voltage of a 6 to 15 V source by 2 in order to obtain a symmetrical...