RESISTANCE CONTROLLABLE INDICATOR

• US 3,758,855 A
• Filed: 07/09/1970
• Issued: 09/11/1973
• Est. Priority Date: 07/09/1970
• Status: Expired due to Term

• Current Assignee: Richard R. Meyer
• Original Assignee: Richard R. Meyer
• Inventors: Meyer, Richard R.
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/053,438
• Time in Patent Office: 1,160 Days
• Field of Search: 324/65,51 331/65,111,66 340/235,384E
• US Class Current: 324/707
• CPC Class Codes: G01R 27/02 Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant by measuring phase angle only G01R25/00

Abstract

A resistance controllable indicator involving a frequency generating circuit wherein the frequency is a function of resistance, the circuit including a pair of spaced terminals normally defining infinite resistance between them and across which, the resistance may be altered on the occasion of and in response to certain phenomena to be indicated and which involve changes in electrical resistance conductivity. No on-off switch is necessary to preserve battery power during periods when not in use.

Claims

1. A resistance controllable indicator comprising a transistorized frequency generating circuit whose frequency is determined by resistance and reactance, said frequency generating circuit including a transistor of the silicon type having base, emitter and collector electrodes and characterized by having low leakage, a power source and indicator, means connecting said emitter and collector electrodes in circuit with said power source and indicator, a second transistor and circuit in signal supply relationship to the base electrode of said first transistor, said second transistor being also of the silicon type having base, emitter and collector electrodes and characterized by low leakage, means for feeding back from said indicator circuit, to said second transistor, signal energy appearing in said indicator circuit, said second transistor circuit comprising a normally open circuit defined by a pair of spaced contacts determining substantially infinite resistance whereby to provide a standby condition with negligible battery drain and without the use of an on/off switch, and means for connecting a lower order of resistance across said spaced contacts to draw sufficient current to produce a response from said indicator in accordance with said lower order of resistance.

2. A resistance controllable indicator in accordance with claim 1, characterized by said feed back means comprising a capacitor in circuit between said indicator circuit and the base electrode of said second transistor, and further characterized by said second transistor circuit including said spaced contacts, being connected from one side of said power source to the base electrode of said second transistor.

3. A resistance controllable indicator in accordance with claim 2, characterized by a case enlosing said frequency generating circuit, with said spaced contacts Mounted on the wall structure of said case to provide externally accessible terminals.

4. A resistance controllable indicator in accordance with claim 3, characterized by said externally accessible terminals being in the form of contact strips affixed to a wall of said case and exposed to manual contact.

5. A resistance controllable indicator in accordance with claim 2, characterized by said frequency indication means as including a speaker.

6. A resistance controllable device in accordance with claim 2, characterized by said practically infinite resistance comprising a base plate of insulation and a pair of wires arranged in spaced relationship to each other on said plate.