The AVRQ family provides a high voltage pulse with a linear leading edge, followed by a slower exponential decay back to zero. The transition time (10%-90%) of the leading edge is variable from 50 ns to 500 ns. The adjustable linear edge makes the AVRQ ideal for testing the common mode transient immunity of optocouplers and other devices. The AVRQ series is also suitable for a range of other applications requiring a high-voltage sweep waveform, such as sweep-control of particle beam systems.
The AVRQ-1-B generates a -1000 V pulse into capacitive loads of up to 40 pF. The 10%-90% rise time of the leading edge is variable from < 50 ns to > 500 ns.
Approximately 1 microsecond after the start of the leading transition, the voltage starts to decay back to zero. The fall time of this decay is at least ten times greater than the rise time of the leading edge. The pulse repetition frequency is adjustable from 1 Hz to 10 Hz, using the front panel controls or by computer command.
This instrument may also be triggered by an external TTL trigger pulse (10 Hz maximum), by a computer command, or by a front-panel pushbutton.
The AVRQ-1A-B is identical to the AVRQ-1-B as well, except that the leading edge rise time is variable over a range of 25 ns to 400 ns (instead of 50 to 500 ns), providing amplitude / rise time ratios of up to 40 kV / us.
On all models, the output will only remain active for 90 seconds after being enabled from the front panel or by computer command. After that time, the output will be disabled. The output must be re-enabled from the front panel or by computer command for the next test.
A delay control and a sync output are provided for oscilloscope triggering purposes. The sync output (a BNC connector located on front panel) provides a TTL pulse with 100 ns pulse width, and will drive 50 Ohms.
The delay between the main output signal and the sync output is variable from 0 to 1.0 seconds.
These models require a high-impedance load. They will not operate correctly into lower resistances, or into loads with more than 40 pF of capacitance (including the cabling and oscilloscope probe capacitance). If the load capacitance is significantly less than 40 pF, some capacitance may need to be added to the device under test to achieve the full rise time adjustment range. The rise time is not a calibrated value due to the influence of the load capacitance – it must be measured with an appropriate high-voltage oscilloscope probe system.