About code locks wrote more than once. However, most of them are difficult to repeat. Design suggested by our Bulgarian friends (the journal “Radio Television Electronics”), devoid of this shortcoming. For opening this lock simply insert the key and complete the circuit with the resistor R1 a certain value (it is mounted in the housing of the key). If the resistance will be different from that specified on the schematic, the relay does not work and the lock will not unlock.
Lock in idle mode (no key) consumes Ocala 16 mA and 24 mA with the key.
Relay — 6V, 20 mA. Transistors V1, V3 — low-power silicon, for example, KT315 with any alphabetic index.
Recommend to read
SHOT ACS. The YEAR 1938
The beginning of the great Patriotic war, the worker-peasant Red army came no powerful self-propelled artillery installations (SAU), although the Finnish war showed the urgent need. The...
BETWEEN “VICTORY” AND ZIS
Sixty-nine years ago, the Gorky automobile plant received the assignment to develop a new six-passenger model. She had to fill the gap between mass four-cylinder "Victory" and...
