Multi-function tester

A multi-function tester for testing for electrical continuity and the presence of various types of voltages comprising:

• a DC voltage source for providing electrical DC-voltage;
• a bistable flip flop circuit having a set input terminal, a reset input terminal, and an output terminal, said output terminal being switchable between a first output voltage-level state and a second output voltage-level state by application of respective voltage changes at said set and reset input terminals, said bistable flip flop circuit being coupled to said DC voltage source and powered thereby, said set input terminal also being coupled to a set voltage divider circuit extending between said DC voltage source and a common terminal, said set voltage divider circuit having a set fixed resistor therein;
• an indicator means coupled between said output terminal and said common terminal for producing a detectable output when said first output voltage level appears at said output terminal;
• a voltage steerable switch means coupled in said set voltage divider circuit for selectively immediately decreasing a switch impedance in response to a steering voltage of a first magnitude being applied to a switching terminal thereof and immediately increasing said switch impedance in response to a steering voltage of a second magnitude being applied to said switching terminal thereof to thereby change the voltage appearing at said set input terminal to move said flip flop between said first and second output voltage level state;
• a voltage probe coupled to said voltage source;
• a common probe coupled to said common terminal;
• a switching probe coupled to said switching terminal;
• wherein each of said voltage, common and switching probe can be selectively brought into contact with each other and can be brought into contact with electrical circuits to be tested;
• whereby voltage signals from both said DC voltage source and from outside sources can be placed on said switching terminal with said voltage, common and switching probes, both directly and through other circuits, for immediately changing the voltage at said flip flop circuit set input terminal in a sense for causing said first level voltage to appear at said output terminal to thereby cause said indicator means to produce a detectable output and voltage signals can be removed from said switching terminal for immediately changing the voltage at said flip-flop circuit set input terminal in a sense for causing said second level voltage to appear at said output terminal to thereby extinguish said indicator means.