In this interesting circuit from Popular Electronics, the output voltage is the square root of the input voltage. Equivalent operational amplifiers can be tried out.
This simple 1 transistor circuit was found in an American documentation from the 60's. The...
Found in a magazine 73 for radio amateurs, this circuit makes use of general purpose transistors and...
The presented circuit allows to control the valve of a tap. The positioning of the emitter and the...