Features

All WPI stimulus isolators are designed to supply constant current because current threshold (not voltage) is the most quantitatively reproducible parameter for stimulation of nerve and muscle. Model A395 dispenses current reproducibly from its Output terminals; the amplitude being determined by the selected current RANGE and the input voltage. Current amplitude is “constant”, that is, load resistance independent, provided that the I x R (load) product does not exceed the available battery supply voltage. A visual indicator (the compliance LEDs) displays if I x R reaches this limit. When the unit is out of compliance, one of the two LEDs (labeled - and +) illuminate, depending in which direction the current is flowing.

Output current

Model A395 generates an output current of arbitrary (user-defined) wave shape; DC, AC, pulse, and combinations thereof. Battery operated, and photoelectrically-isolated from the input voltage drive, the instrument regenerates output currents which are linearly proportional to the analog voltage waveforms provided by your D/A converter or signal generator. The A395 is ideally suited for data acquisition and stimulator generators. It can be easily daisy-chained for mutiple channel requirements.

Current Delivery

A 10 V input produces the maximum output current for the current range selected, i.e., 100 µA, 1mA, or 10mA. Front panel controls allow DC current to be generated. Externally applied signals can be superimposed simultaneously (DC offset). Warning lamps indicate open circuit or excessive current conditions.

Digital Meter

Measures DC or average output current.

Overload Lamps

Indicate when output voltage has reached positive or negative compliance voltage limit. 

Specifications 

INPUT

OUTPUT

Accepts analog input

OUTPUT CURRENT, Imax	3 ranges: 100μA, 1mA, and 10mA
OUTPUT VOLTAGE RANGE	±70V
OUTPUT BANDWIDTH	10 kHz (measured across 1KΩ load R)
INPUT RESISTANCE	>20MΩ
INPUT VOLTAGE @ Imax	±10V
INPUT/OUTPUT LINEARITY ERROR	<0.5%
RISE, FALL TIME	26μs @ 10KΩ
POWER: Model A395D	17 alkaline 9V batteries
POWER: Model A395R	17 rechargeable NiMH 9V batteries
DIMENSIONS	6.5 x 4 x 3.5 in. (16 x 10 x 9 cm)
SHIPPING WEIGHT	4 lb. (1.8 kg)