| 摘要 |
A device turns ON and OFF electrical power in a building in response to entry and exit of people. Four sets of infra red light emitters and receivers supply receiver signals to entry and exit monitor circuits having integrated circuits connected together to deliver down pulses by discrimination between the occurrence of infrared receiver signals. The count pulses are delivered to a counting circuit which is preset by a manually operated switch which supplies a preset signal to a comparator circuits which also receives the signal from the counting circuit to produce an ON-OFF signal. A controller circuit receives this ON-OFF signal and controls the electrical power in an electricity supply line.
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