Low voltage circuit tester
First Claim
Patent Images
1. A circuit tester comprising:
- (a) a reference voltage source that provides a reference voltage;
(b) an indicator having first and second response states, said first and second response states producing first and second indications, respectively;
(c) an indicator driver connected to the reference voltage source, the indicator driver having an input, the indicator driver being connected to drive the indicator in the first response state when a voltage at the input is lower than the reference voltage and connected to drive the indicator in a second response state when the voltage at the input is higher than the reference voltage;
(d) an oscillator having an output electrically coupled to the input of the indicator driver; and
, (e) a probe electrically coupled to the input of the indicator driver;
wherein, when the probe is not electrically connected to a circuit under test, the oscillator causes the indicator driver to cycle the indicator between the first and second response states.
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Abstract
A circuit tester comprises a reference voltage source, an indicator with first and second response states, an indicator driver connected to the reference voltage source, an oscillator and a probe. The oscillator'"'"'s output and the probe are both connected to the indicator driver'"'"'s input. The indicator driver drives the indicator in the first response state when the voltage at the input is lower than the reference voltage, and in the second response state when the voltage at the input is higher than the reference voltage. The oscillator causes the indicator driver to cycle the indicator between the first and second response states when the probe is not connected to a circuit under test.
13 Citations
38 Claims
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1. A circuit tester comprising:
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(a) a reference voltage source that provides a reference voltage;
(b) an indicator having first and second response states, said first and second response states producing first and second indications, respectively;
(c) an indicator driver connected to the reference voltage source, the indicator driver having an input, the indicator driver being connected to drive the indicator in the first response state when a voltage at the input is lower than the reference voltage and connected to drive the indicator in a second response state when the voltage at the input is higher than the reference voltage;
(d) an oscillator having an output electrically coupled to the input of the indicator driver; and
,(e) a probe electrically coupled to the input of the indicator driver;
wherein, when the probe is not electrically connected to a circuit under test, the oscillator causes the indicator driver to cycle the indicator between the first and second response states. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A circuit tester comprising:
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(a) first, second and third connectors;
(b) first, second, third, fourth, fifth and sixth diodes, each diode having an anode and a cathode, the anodes of said first, third and fifth diodes connected to said first, second and third connectors, respectively, and the cathodes of said second, fourth and sixth diodes connected to said first, second and third connectors, respectively; and
,(c) a testing circuit having a positive input, a negative input, and a probe input;
wherein the cathodes of said first, third and fifth diodes are connected to the positive input of said testing circuit, and the anodes of said second, fourth and sixth diodes connected to the negative input of said testing circuit, and one of said connectors is connected to the probe input of said testing circuit.
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22. A circuit tester comprising:
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a full-wave rectifier circuit having a pair of inputs, a positive output and a negative output;
a probe;
a first and second diode each having an anode and a cathode, the first diode having its anode connected to the probe and its cathode connected to the negative input, the second diode having its anode connected to the positive input and its cathode connected to the probe;
a voltage divider connected between the positive and negative outputs;
the voltage divider having a reference voltage output;
first and second comparators each having an inverting input and a non-inverting input, the reference voltage output coupled to the inverting input of the first comparator and the non-inverting input of the second comparator and the probe coupled to the non-inverting output of the first comparator and the inverting input of the second comparator;
an oscillator providing a signal, the signal periodically varying about the reference voltage and coupled to the probe through a series impedance; and
,a two-color light emitting diode coupled between outputs of the first and second comparators.
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23. A method of testing a circuit, the method comprising:
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(a) producing a reference voltage;
(b) providing a tester circuit comprising an indicator, an oscillator and a probe, the indicator having first and second response states;
(c) connecting the probe to a test point on a circuit under test; and
,(d) producing an indication from the indicator in response to a voltage at the test point, wherein when the voltage at the test point is lower than the reference voltage the indication comprises the first response state, and when the voltage at the test point is higher than the reference voltage the indication comprises the second response state, and when the test point is floating the indication comprises cycling between the first and second response states at a frequency determined by the oscillator. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A method of testing a circuit, comprising:
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(a) producing a reference voltage;
(b) providing a test circuit comprising a first, a second and a third display element, a display element driver and a probe;
(c) connecting the probe to a test point on a circuit under test; and
,(d) activating one of said display elements, wherein when a voltage at the test point is lower than the reference voltage the display element driver activates the first display element, and when a voltage at the test point is higher than the reference voltage the display element driver activates the second display element, and when the test point is floating the display element driver activates the third display element.
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Specification