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High Voltage Isolator
Tektronix A6907 / A6909 High Voltage Isolators

Produced from 1995 to (?)

(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix A6907 / A6909 High Voltage Isolators connect “floating” (not referenced to ground) signals to an oscilloscope or digitizer for measurement.

The A6907 has four, the 6909 has two input channels.

The A6907/A6909 include special probes with an in-cable balun for shielding against large dv/dt fields. These probes are specific to the A6907/A6909.

Optionally, an A620 current probe can be connected.

Key Specifications

Bandwidth DC to 60 MHz (100 and 200 mV ranges: 50 MHz)
Deflection 100 mV/Div to 200 V/Div, 1-2-5 (scope input @ 100 mV/Div)
Normal mode voltage max. 850 V (DC + peak AC)
Common mode voltage (channel to chassis) 850 V (DC + peak AC) or 600 V (ACRMS); derate at 20 dB/decade from 500 kHz to 60 MHz
Common mode voltage (between channels) 1700 V (DC + peak AC) or 1200 V (ACRMS)
CMRR 105 dB @ 60 Hz, 60 dB @ 1 MHz, 50 dB @ 10 MHz
Common mode slew rate 20 kV/ms
  • Self-calibration
  • Portable
  • GPIB interface standard on the A6907 (option 10 on the A6909)


Optical couplers, insulated transformers, and plastic barriers are used for extremely high isolation between channels and the chassis, and from channel to channel.

An electrical-to-optical (E/O) converter isolates the signal and converts it to an optical analogue. An optical-to-electrical (O/E) converter demodulates the optical signal to an electrical signal whose common mode elements have been rejected. The E/O converter uses a low-contact DC to DC converter as a power source to provide a high degree of isolation.