We found this mixer in an American documentation. Operational amplifier supports equivalent and changed number of inputs. Power can be between 6 and 12 V.
Found in Radio Electronics from the 90s, this circuit uses a thermistor as a sensor that can have...
This automatic brightness control that uses an LDR as a sensor, was found in American...
This circuit is from a Radio Electronics from April 1964. Note the unijunction transistor of the...