Method for contactless measurement of a resistance arranged in the secondary circuit of a transformer and device for carrying out the method
First Claim
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1. Method for the contactless measuring of a resistance arranged in a secondary circuit of a transformer with inductively coupled coils having a primary and secondary side in a motor vehicle, comprising the steps of:
- exciting a resonant circuit, which is connected to a resistance to be measured on the secondary side of the transformer, by an excitation signal from a primary side of the transformer,interrupting the excitation signal,sensing a decaying excitation response at the primary side anddetermining, as a function of time constant of the decaying excitation response sensed at the primary side, a value of the resistance to be measured.
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Abstract
A method and a device for transmitting and for measuring resistance values, is particularly provided for use in motor vehicles, for the constant control of airbag systems. In the method and device an exciter signal coupled into a secondary-side resonant LCR circuit from the primary side via inductively coupled coils is interrupted, transmitted back to the primary side of the transformer and is there used for determining the resistance value by evaluating the time constant of the exciter response.
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Citations
20 Claims
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1. Method for the contactless measuring of a resistance arranged in a secondary circuit of a transformer with inductively coupled coils having a primary and secondary side in a motor vehicle, comprising the steps of:
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exciting a resonant circuit, which is connected to a resistance to be measured on the secondary side of the transformer, by an excitation signal from a primary side of the transformer, interrupting the excitation signal, sensing a decaying excitation response at the primary side and determining, as a function of time constant of the decaying excitation response sensed at the primary side, a value of the resistance to be measured. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Device for the contactless measurement of a resistance arranged in a secondary winding of a transformer with airgap between a primary winding and a secondary winding comprising:
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(a) a first resonant LC circuit means connected to the secondary winding together with the resistance to be measured; (b) an exciter means connected to the primary winding for providing an excitation signal that can be switched off to the primary winding; and (c) analyzing means connected to the primary side of the transformer, for measuring a primary voltage after the excitation signal has been switched off to determine as a function of a time constant of a decaying excitation response at the primary side, a value of a resistance to be measured. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification