JPS5543338A - Bath buzzer - Google Patents

Abstract

PURPOSE: To assure the operation of a bath buzzer, by using a Schmidt circuit having two transistors whose emitters are coupled to each other.

CONSTITUTION: A loudspeaker 12 is connected to the Schmidt circuit through an interlock switch 2, a water leakage detection transistor 3, a transistor 4 for battery testing, water level action and water leakage action, a water leakage electrode 13, a water level electrode 14, a common electrode 15, a temperature detection circuit 16, 36, 37 and a non-stable multivibrator circuit. The Schmidt circuit comprises the transistors 5, 6 whose emitters are coupled to each other. The non-stable multivibrator circuit comprises transistors 7, 8, 10, 11. A voltage fall compensation silicon diode 31 connected between the anode of a DC power source 1 and the connection point of base resistors 29, 30 for the transistor 5 reduces the fluctuation in the temperature of operation due to that in the voltage of the DC power source 1. A part of the collector voltage of the transistor 6 is positively feedbacked to a battery voltage detection circuit to eliminate the fluctuation in the sound of the loudspeaker.

COPYRIGHT: (C)1980,JPO&Japio