| 摘要 |
A resistance or voltage tester for producing an audible tone that varies inversely with resistance or voltage. The device comprises an audible wide range resistance and medium range voltage tester in the form of a rectangular small box designed to fit into a shirt pocket. The tester includes a speaker driven by low current logic gates and a transistor. The frequency of the speaker varies inversely proportional to the measured resistances ranging from zero to over 50 megohms and also inversely proportional to the voltage measured. In particular cases, the device can also be used as an audio signal source and with the use of a suitable probe the voltage range can be increased to +400 VDC or 260 VAC.
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