Electrical line interruption detection and alarm circuit
First Claim
1. A circuit for detecting excessive impedances between a body under test and an input of a signal processing device which contains an amplifier, said signal processing device being connected to said body by a low impedance electrical connection, and said input having a voltage applied thereto by said connection comprising:
- (a) a supply circuit to supply a variable auxiliary DC current to said electrical connection, said circuit operating to increase said current with increasing voltage at said input; and
(b) an alarm device which generates an alarm indicating excessive impedance when said input voltage is outside a predetermined range.
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Accused Products
Abstract
A circuit for detecting and indicating an interruption in the electrical connection between a signal device and a signal processing device, which has been provided with an amplifier at its input. The signal device has a relatively low impedance and the signal processing device has a relatively high impedance. The circuit includes an alarm device which generates an alarm when the predetermined upper limit of the amplifier input voltage has been exceeded. Also included are a supply circuit to feed an auxiliary dc current into the connection between the signal device and the signal processing device. The supplied auxiliary current is controlled by the amplifier input voltage to rise during an increased amplifier input voltage. As a result, a lower current supply can be provided under normal circumstances, which reduces misinterpretations. Preferably, the circuit is used in connection with ECG measuring devices.
39 Citations
14 Claims
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1. A circuit for detecting excessive impedances between a body under test and an input of a signal processing device which contains an amplifier, said signal processing device being connected to said body by a low impedance electrical connection, and said input having a voltage applied thereto by said connection comprising:
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(a) a supply circuit to supply a variable auxiliary DC current to said electrical connection, said circuit operating to increase said current with increasing voltage at said input; and (b) an alarm device which generates an alarm indicating excessive impedance when said input voltage is outside a predetermined range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification