| 摘要 |
PURPOSE: An alarm device for prevention of collision is provided to include transceiver circuit for minimizing possible minimum sensing distance which is representative of minimum distance which ultrasonic sensor can sense. CONSTITUTION: The sensor driving part(12) has a transistor(TR1) which is supplied with output signal of the oscillator(11) through the resistor(R2) and is switched and a transformer(TRANS1). The transformer has a primary coil(L1) which is supplied with power from power supply(Vcc) through the resistor(R) by the switching operation of the transistor(TR1) and a secondary coil(L2) having predetermined turns ratio for the primary coil. The pre-amplifier(14) has a capacitor(C1) connected to input terminal and a resistor(R3) parallel to the capacitor.
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