JPS55104763A - Apparatus for measuring electric circuit - Google Patents

Abstract

PURPOSE: To eliminate notifying means and prevent in advance an accidental drive of an apparatus for measuring an electric circuit by so constructing the apparatus as to distinguish the electric state of a portion to be measured according to sound and enabling the approximate measurement of the apparatus body without movement of a sight line at all.

CONSTITUTION: A detecting circuit 2 having a detection pointer 1 detects the voltage level of a circuit to be measured to detect whether the electric state of the circuit is high or low level and whether the circuit produces single pulse or pulse train. When the circuit is, for example, high level, a detection signal is introduced to a NAND gate 8. Since the gate 8 is in open standby state with the output from an oscillator circuit 3 and the inhibit output from a monostable multivibrator 5 as a pulse expanding circuit, the circuit 8 is opened and a speaker 15 produces a sound of oscillating frequency f₁ of the circuit 3. When the circuit is, for example, low level, the speaker 15 produces a sound of oscillating frequency f₂ of an oscillator circuit 4. When the circuit produces a single pulse, the speaker produces a sound of frequency f₁ as designated in Fig. A or B. When the circuit produces a pulse train, the speaker produces a sound of frequency f₂ as designated by Fig. C. This apparatus may measure whether the circuit produces single pulse or pulse train by hearing the sound.

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