This circuit is temperature stabilized. Modern equivalent transistors can be used, and the power supply can actually be between 9 and 12 V. The circuit is from an old documentation.
The frequency of the blinking of this circuit is given by the capacitor that can have its value...
This low-current power supply was obtained in Japanese documentation from 1968. The currents are...
This simple audio booster came out in a Popular Electronics in the 90s. It serves as a booster for very...