Potential-free HV switching measurer - uses electro-optic coupler driven by voltage modulated frequency provided by analogue memory via optic fibre

摘要

The circuit makes potential-free measurements of h.v. switching processes. A control unit triggers both a thyristor through an electro-optic coupler and an oscilloscope. The thyristor voltage is tapped through a voltage divider by a sample and hold amplifier. The output passes through an analogue multiplexer, a voltage-frequency converter, an electro-optic coupler and a frequency-voltage converter to the oscilloscope. This procedure avoids measurement errors due to non-linearity, temp. effects and insufficient electro-optic band-width which appear in systems without modulation.