Patent ID: 6969997

Claim:
A power source test instrument for a circuit comprising: a voltage test circuit comprising: a first operational amplifier with a positive input terminal connected to a voltage source; a first set of relays with a first terminal connected to a negative input terminal of the first operational amplifier, a second terminal connected to an output terminal of the first operational amplifier, and a third terminal grounded via a first resistor; a second set of relays with a first terminal connected to a third terminal of the first set of relays, a second terminal grounded, and a third terminal; and a third set of relays with a first terminal connected to an output terminal of the first operational amplifier, a second terminal connected to a first output terminal of the voltage test circuit, a third terminal connected to the third terminal of the second set of relays, and a fourth terminal connected to a second output terminal of the voltage test circuit; a current test circuit comprising: a second operational amplifier with four resisters connected to form a differential amplifier, wherein the ratio of the resistance between a negative input terminal of the second operational amplifier and the output terminal of the second operational amplifier and the resistance between the negative input terminal of the second operational amplifier and a first input terminal of the differential amplifier, is equivalent to the ratio of the resistance between a ground terminal and a positive input terminal of the second operational amplifier and the resistance between the positive input terminal of the second operational amplifier and a second input terminal of the differential amplifier; and a second resistor connected between the first input terminal and the second input terminal of the differential amplifier; wherein the first set of relays can be switched to turn on the first terminal and the second terminal or to turn on the first terminal and the third terminal, the second set of relays can be switched to turn on the first terminal and the third terminal or to turn on the second terminal and the third terminal, the third set of relays can be switched to turn on the first terminal and the second terminal and to turn on the third terminal and the fourth terminal or be switched to turn on the first terminal and the fourth terminal and to turn on the second terminal and the third terminal.