Pet door with control circuit therefor

摘要: A control circuit for unlatching a door, particularly pet includes transmitter coil (L1), pulse driver (11) energizing the coil, and discriminator (12, 13) detecting a.c. components in current caused by currents induced an outside tuned brought adjacent e.g. around neck of seeking entry, comparing frequency with standard. latch drive (14) responds to operating door if comparison is satisfactory.