This circuit, which can be used as a shield, was found in Radio Electronics from the 90s. The operating circuit can be replaced by a lower voltage equivalent.
This circuit activates an output, which can be a lock, only when a card containing the programmed code...
This circuit was found in Popular Electronics from 1993. The 1458 consists of a double 555. The...
This is a Serial In - Parallel Out or Serial Out [SIPO or SISO] shift register using the...