This circuit generates short pulses. The transistor can be a 2N2222 or BC548 and the frequency is given by the resistors and the capacitor that can be changed.
We found this version of the automotive tachometer in a 1980s publication. Variations from other...
This circuit was obtained from American documentation from 1966. It triggers when the two input...
This circuit allows to increase the output power of a 741 as an amplifier. The circuit is from a...