This timer was found in Japanese documentation from the 1960s. The transistor can be replaced by an equivalent and the relay must be of the sensitive type with voltage according to the power supply.
This configuration is also valid for other operators and the formula for calculating the gain is...
This inductively coupled oscillator was found in an American documentation from the 90's. The...
This circuit was obtained from an Analog Devices manual from the 90's. The integrated circuit is...