The Digitimer High Voltage Stimulator model DS7A provides constant current high voltage pulses of brief duration for percutaneous stimulation during investigation of the electrical activity of nerve and muscle tissue

The output current is continuously variable over the range 0 to 100 milli-Amps, from a source voltage continuously variable from less than 100 Volts to 400 Volts, to meet the requirements of human pathological cases

Short pulse durations have been made available to minimise any discomfort to the subject

The pulse duration can be varied from 50 microseconds to 2 milli-seconds in six steps and a specially designed isolated output stage maintains a square (current) pulse shape while minimising stimulus artefacts

The instrument is mounted in a non-conductive, free standing case and is mains powered

For higher voltages, the Digitimer stimulator model D185 is suggested

The DS7AH option, allowing currents up to 1A with a maximum pulse duration limit of 200 micro-seconds, is also available

This model is offered to overcome the difficulties of stimulating deep peripheral nerves, or large muscles such as the quadriceps, with large area electrodes

The stimulator requires a TTL trigger pulse input and triggers on the positive edge (negative edge can be factory set). Alternatively a foot switch may be connected to a socket on the rear panel or the front panel push button pressed

A TTL compatible trigger output is provided at a BNC socket on the rear panel