Domestic electrical tester

Claim 2

An electrical testing device, comprising: at least a first, second and third measuring terminal pairs; circuit means connected to said measuring terminal pairs for measuring a respective electrical parameter by means of each of said terminal pairs, said circuit means operating differently depending on which of said measuring terminal pairs are used for a measurement; indicating means connected to said circuit means for indicating the result of a measurement using one of said measuring terminal pairs; said circuit means being responsive to: (a) said first pair of measuring terminals to energize said indicating means when an applied voltage thereat is in a first predetermined voltage range; (b) said second pair of measuring terminals to energize said indicating means when an applied DC voltage thereat is in a second predetermined voltage range; and, (c) said third pair of measuring terminals to energize said indicating means when a resistance applied across said third pair of measuring terminals is below a first predetermined value.

Claim 3

An electrical testing device as in claim 1, further comprising fourth and fifth measuring terminal pairs and wherein said circuit means is further responsive to: (d) said fourth pair of measuring terminals to energize said indicator means in response to a voltage thereat in a third voltage range; and, (e) said fifth pair of measuring terminals to energize said indicator means when a resistance applied across said fifth pair of measuring terminals is below a second predetermined value.

Claim 4

An electrical testing device as in claim 1 wherein said first predetermined voltage range is approximately 110-240 volts.

Claim 5

An electrical testing device as in claim 1, wherein said second predetermined voltage range is approximately 1.5 to 6 volts.

Claim 6

An electrical testing device as in claim 1, wherein said first predetermined value is approximately 8K ohms.

Claim 7

An electrical testing device as in claim 2, wherein said third voltage range is approximately 6 to 15 volts.

Claim 8

An electrical testing device as in claim 2, wherein said second predetermined value is approximately 200 ohms.

Claim 9

An electrical testing device as in claim 1, wherein said pairs of measuring terminals, said circuit means and said indicating means are contained in a common housing, with said terminal pairs being connected to electrical connectors for connection with test leads, said indicator means comprising a lamp viewable from outside said housing.

Claim 10

An electrical testing device as in claim 1, wherein said circuit means comprises: first and second resistors respectively connected at first ends thereof to said first pair of measuring terminals, said third pair or measuring terminals being connected respectively to second ends of said first and second resistors, said second end of said first resistor being connected to a first side of a voltage source; a resistance divider formed by third and fourth resistors connected to one another at first ends thereof, said third resistor being connected at a second end thereof to the second end of said second resistor, said fourth resistor being connected at a second end thereof to a second side of said voltage source, said second pair of measuring terminals being respectively connected to the second ends of said third and fourth resistors; a transistor having a base connected to the connected first ends of said third and fourth resistors and an emitter connected to said second side of said voltage source; and a fifth resistor connected at a first end to a collector of said transistor, said indicating means being respectively connected to said first side of said voltage source and a second end of said fifth resistor.

Claim 11

An electrical testing device as in claim 2, wherein said circuit means comprises: first and second resistors respectively connected at first ends thereof to said first pair of measuring terminals, said third pair of measuring terminals being connected respectively to second ends of said first and second resistors, a second end of said first resistor being connected to a first side of a voltage source; a resistance divider formed by third and fourth resistors connected to one another at first ends thereof, said third resistor being connected at a second end thereof to the second end of said second resistor, said fourth resistor being connected at a second end thereof to a second side of said voltage source, said second pair of measuring terminals being respectively connected to the second ends of said third and fourth resistors; a transistor having a base connected to the connected first ends of said third and fourth resistors and an emitter connected to said second side of said voltage source; a fifth resistor connected at a first end to a collector of said transistor, said fifth pair of measuring terminals being respectively connected to said collector and said second side of said voltage source; and a sixth resistor having a first end connected to said first side of said voltage source, said fourth pair of measuring terminals being respectively connected to a second end of said sixth resistor and said collector, said indicating means being respectively connected to said first side of said voltage source and a second end of said fifth resistor.

Claim 12

An electrical testing device, comprising: a plurality of measuring terminal pairs; circuit means connected to said measuring terminal pairs for measuring a respective electrical parameter by means of each of said terminal pairs, said circuit means operating differently depending on which of said measuring terminal pairs are used for a measurement, said circuit means including only one transistor which is responsive to an electrical parameter measured with at least one of said plurality of measuring terminal pairs; and indicating means connected to said circuit means for indicating the result of a measurement using one of said measuring terminal pairs, said indicating means including only one lamp which is connected to said circuit means.

Claim 13

An electrical testing device, comprising: a plurality of measuring terminal pairs; circuit means connected to said measuring terminal pairs for measuring a respective electrical parameter by means of each of said terminal pairs, said circuit means operating differently depending on which of said measuring terminal pairs are used for a measurement, said circuit means including only one transistor which is responsive to an electrical parameter measured with at least one of said plurality of measuring terminal pairs; and indicating means connected to said circuit means for indicating the result of a measurement using one of said measuring terminal pairs, said indicating means including only one lamp which is connected to said circuit means.