Electronic locking system with an access-control solenoid

摘要

An electronic locking system with an access-control solenoid for controlling the operation of a locking mechanism is substantially immune to "hot-wiring." The locking system includes an actuating circuit for energizing the access-control solenoid. The actuating circuit is responsive to a modulated drive signal of a selected frequency to apply current through the solenoid to retract its plunger, while blocking externally applied DC voltages from reaching the solenoid. When an access code is entered through an input device, a control circuit of the locking system verifies the access code. When the code is verified, the control circuit generates the modulated drive signal to energize the solenoid to retract the plunger, thereby allowing the locking mechanism to be unlocked. After the plunger is retracted, the frequency of the modulated drive signal is changed to reduce the power consumption for retaining the plunger in its retracted position.