This circuit was found in old documentation. Transistors can be BC548. The LEDs are the same.
This circuit was found in documentation from the 1970s. However, it can be implemented with modern...
The operational of this amplifier can be the 741 and the resistors R1 and R3 are of 10 k. R2B is...
This well-known circuit triggers a relay when light striking the phototransistor is cut off. The...
