Electric alarm clock with piezoelectric buzzer - incorporates integrated logic circuit designed for mass prodn.

摘要

The buzzer uses a piezoceramic sound generator (1) coupled to the DC battery via a release button (2) and an integrated logic module (3). This has an AND gate (G2) in series with the release button (2) with a stable multivibrators coupled to its inputs. Each multivibrator uses two series logic gates (G1, G2; G3, G4) each with two inputs, with the output gate (G2, G4) of each multivibrator coupled to the input gate (G1, G3) via a feedback capacitor (C1, C2.) Each output gate (G2, G4) also has its own feedback loop using the same capacitor (C1, C2) in series with a resitor (R1, R2). The output gate (G2) of one of the multivibrators is provided by the AND gate.