| 摘要 |
PURPOSE: To measure the resistance of a resistor in the secondary circuit of a transformer by energizing an oscillation circuit connected with the resistor on the secondary of transformer from the primary thereof, cutting off the energizing signal and then returning an attenuating energizing response to the primary. CONSTITUTION: A secondary LCR series oscillation circuit 4 is energized with a short duration current pulse, e.g. limited number of sinusoidal oscillation, through a transformer 2. Since the transformer 2 has primary 6 closed with a high resistor, it provides only the function of inductance connected in series with a coil L. Attenuated oscillation takes place in the circuit 4 and the attenuation depends not on the coupling with the transformer 2 but on the quantities R' and L'. An equivalent circuit of attenuating oscillation can be obtained on the primary. A time constantτ=2L'/R' is a measure of secondary resistance which must be obtained irrespectively of the coupling characteristics of transformer 2. Subsequently, peak value U0 of response is determined and the oscillation is counted until a predetermined threshold U0 /m, e.g. U0 /2, is reached. Finally, envelope of response is formed and the interval between two predetermined limits is measured. |
