ELECTRONIC SWITCH AND ULTRASONIC IMAGING UNIT USING THE SAME

摘要

PROBLEM TO BE SOLVED: To reduce an AC leakage in the case of interruption by PN joining in an electronic switch. SOLUTION: The electronic switch is constituted by connecting an off control circuit and an AC signal escape circuit to a transmission circuit. The off control circuit is constituted of a bipolar transistor Q2 and an R5 for electrically connecting a part between the emitter and the base of the bipolar transistor Q1, inserting a part between the collector and the base of the transistor Q1 to an AC signal transmitting circuit and impressing an inverse directional bias on a part between the collector and the base of the transistor Q1 in response to an AC signal interrupting instruction. The AC signal escape circuit is grounded via a serial circuit consisting of the bipolar transistor Q2 and a capacitor C4, which is turned on in response to the interrupting instruction.