Switchable automotive circuit test light

• US 4,999,574 A
• Filed: 11/01/1989
• Issued: 03/12/1991
• Est. Priority Date: 11/01/1989
• Status: Expired due to Fees

• Current Assignee: Edward L. Stephens
• Original Assignee: Edward L. Stephens
• Inventors: Stephens, Edward L.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Regan, Maura K.
• Application Number:
  US07/429,967
• Time in Patent Office: 496 Days
• Field of Search: 324/133, 324/503, 324/433, 324/402, 324/556, 340/650, 340/652
• US Class Current: 324/133
• CPC Class Codes: G01R 19/16557 Logic probes, i.e. circuits indicating logic state (high, low, O); modifications of electronic switches or gates for indicating state of switch H03K17/18
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00

Abstract

A tool for automotive technicians to use to diagnose electrical problems on automobiles. That is easer to use, faster, and far more accurate. This tool comprises of a case to hold probe, circuit, LED'"'"'s and a means to connect said tool to an automobile. Two lights, first light to tell the operator the tool is ready for use and that the electrical connections to the storage battery are complete to the second light. Second light illuminates when said probe is in contact with automobile system and continuity of said circuit exists. A switch on said tester to select current direction of said tester. Tester circuit which is lower thatn 20 milli amps. when in series or parallel with the automotive circuit being tested.

Claims

1. A portable hand held continuous self monitoring circuit tester, for detecting problems in automotive 12 volt electrical systems, computer controlled circuits comprising:

a case rectangular in shape, one end having an electrically conductive probe, the other end having first and second of electrical leads

said first electrical lead connecting to the positive side of a storage battery of the automotive system being tested

said second electrical lead connecting to the negative side of a storage battery of the automotive system being tested;

an upper portion of said case having first and second light emitting diodes, and a double pole double throw switch protruding through said case

said first light emitting diode to continuously monitor said electrical leads

said second light emitting diode used in testing the automotive system;

first, second, and third electrical circuits enclosed in said case

said first circuit comprising said first light emitting diode in series with a first current limiting resistor of approximately 680 ohms connected between said first and said second electrical leads

said second circuit comprising said second light emitting diode in series with a second current limiting resistor of approximately 680 ohms connected between the electrical probe through the switch to said first electrical lead

said third circuit comprising said second light emitting diode in series with said second current limiting resistor of approximately 680 ohms connected between the electrical probe through said switch to said second electrical lead;

said switch to change from said second to said third circuit.

2. The circuit tester of claim 1 wherein said electrical circuit has a less than 17 milliamps when in series or parallel with the automotive system being tested.