This is the traditional audio preamp configuration with the National Semiconductor LM382. The circuit has good gain and can be used with magnetic pickups or from signals from an auxiliary input.
Here is a very simple robot circuit that follows the line driven by a small 3 V sevomotor that...
This circuit, which provides a power of up to 3.5 W, can be supplied with voltages from 9 to 14 V....
This circuit transmits the signal taken from a telephone line to a receiver placed nearby (up to a...