CONTINUITY TESTER

• US 3,831,089 A
• Filed: 10/10/1973
• Issued: 08/20/1974
• Est. Priority Date: 08/20/1971
• Status: Expired due to Term

• Current Assignee: George Pearce
• Original Assignee: George Pearce
• Inventors: Pearce, George
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/404,851
• Time in Patent Office: 314 Days
• Field of Search: 324/122,133,51 340/252R,255,256
• US Class Current: 324/122
• CPC Class Codes: G01R 19/145 Indicating the presence of current or voltage
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/54 Testing for continuity

Abstract

A multi-test, handheld instrument for testing the continuity of an electrical circuit utilizes an indicator lamp which lights when continuity is present. The instrument also serves as a voltmeter by causing a neon lamp to flash at a rate dependent upon the impressed voltage. The instrument contains a battery as its power source and is arranged to prevent discharge of the battery when the test leads are inadvertently or deliberately shorted together.

Claims

1. Apparatus for indicating the presence of line voltage and continuity comprising, first and second conducting leads for connection to an external circuit that may provide line voltage between said leads, impedance means permanently connected between said first and second leads for limiting the current through said first and second leads to a nondamaging value when line voltage is applied therebetween, first indicating means electrically coupled to said impedance means for indicating the presence of line voltage when said first and second conducting leads are connected to a source thereof, said impedance means including capacitive means for receiving a charge through means including said first and second leads when said leads are connected to a low impedance of magnitude much less than that of said impedance means, second indicating means for indicating continuity when the charge carried by said capacitive means changes, means including a battery and said first and second leads when said leads are connected to a low impedance of magnitude much less than that of said impedance means for selectively coupling charge to said capacitive means, and switching and electrically coupled to said capacitive means and said second indicating means for causing said second indicating means to indicate continuity in response to a predetermined change in the charge carried by said capacitive means.

2. Apparatus for indicating the presence of line voltage and continuity in accordance with claim 1 wherein said switching means comprising a controlled rectifier connected in series between said second indicating means and said battery means and having its gate electrode coupled to said capacitive means for rendering said controlled rectifier conductive in response to a change in the charge carried by said capacitive means.

3. Apparatus for indicating the presence of line voltage and continuity in accordance with claim 2 and further comprising a switch in series with said controlled rectifier and said battery means.

4. Apparatus for indicating the presence of line voltage and continuity in accordance with claim 3 and further comprising a resistor shunting said capacitive means to provide a discharge path for said capacitive means.

5. Apparatus for indicating thE presence of line voltage and continuity in accordance with claim 4 and further comprising means for recharging said battery means by connecting said first and second conducting leads to a suitable electric potential source, the recharging means including a rectifier in series with a current limiting resistor, the recharging means being in series with the battery means across said first and second conducting leads, and the rectifier being poled to permit current to flow in the direction to charge the battery and to block current flow in the reverse direction.