DS7R

Digitimer

Constant Current Research Stimulator

The DS7R is a high-performance constant current stimulator designed specifically for human and animal research applications involving peripheral nerve or muscle stimulation. It delivers brief, high-voltage pulses—up to 999 mA—ideal for investigating the electrical activity of nerves and muscle tissue in experimental settings. Its high output current and extended pulse duration capabilities make it especially suitable for stimulating large muscle groups or deeper nerve structures.

The DS7R combines high current delivery, adjustable pulse durations, and safety-focused features to meet the needs of researchers conducting electrical stimulation studies on human or animal subjects. It’s an ideal tool for laboratories requiring a flexible, non-medical stimulator with exceptional performance and control.

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Key Features

High Output Current: Adjustable over two ranges — 0–99.9 mA and 0–999 mA.
Extended Pulse Duration: Pulse widths from 50 μs to 2 ms, offering flexibility beyond medically certified systems.
400 V Compliance Voltage: Ensures reliable stimulation even under higher impedance conditions.
Flexible Triggering: Accepts TTL-compatible external triggers or manual activation via front-panel push button.
Alternating Polarity Mode: Helps prevent site polarization and minimizes electrolytic effects during prolonged stimulation.

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Integration & Compatibility

The DS7R can be easily integrated into experimental setups and is compatible with a variety of external control systems. It supports TTL-compatible external triggering, allowing seamless synchronization with other devices such as the DG2A Train/Delay Generator. For researchers requiring more advanced stimulus control and the ability to deliver biphasic pulses, the DS8R Biphasic High Voltage Constant Current Stimulator is recommended. Alternatively, for applications where medical certification is required, options such as the DS7A/AH High Voltage Constant Current Stimulators, the DS5 Bipolar Stimulator, or the D185 MultiPulse Transcranial Cortical Stimulator are available.

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Designed for Research Use

While the DS7R is based on the medically approved DS7AH, it offers greater pulse duration flexibility (up to 2 ms vs. 200 μs on the DS7AH), making it suitable exclusively for research. This extended functionality places it outside the EN60601-2-40 limit (50 mJ) applied to evoked potential stimulators, but it remains well within the 300 mJ safety limits set by EN60601-2-10 for therapeutic electrical stimulators.

Stimulus Output

Current Control:	selected by 10 turn dial and x1/x10 switch.: Dial reading 00.0 to 99.9 giving 0 to 100 mA (99.9 mA) for x1 setting and 0 to 1000 mA (999 mA) for x10 setting.
Pulse Duration:	50, 100, 200, 500, 1000, 2000 microseconds (µs)
Pulse Polarity:	Three position toggle switch selects Normal/Reverse/Alternating.
Compliance:	Continuously variable from 100V to 400V.
On/Off Switch:	On is up. Off disables output and open circuits terminals.
Connections:	4 mm shrouded sockets (red and black) on 3/4" centres. Red socket goes positive with reference to
black socket.

Trigger

Rate:	The Maximum trigger rate is 1,000 pps (1 kHz).
Input:	Electrical via Rear Panel BNC socket: Triggers: Logic signal (+3 to 15V) +ve edge, TTL compatible (-ve edge by factory change). Minimum Pulse Duration is 5 microseconds. Front panel: Push button. Rear panel: 3.5mm mono jack socket for contact closure foot switch (contact closure).
Output:	Rear panel BNC, positive TTL pulse, 1 ms (950 ±50µs) wide (can be factory set for a negative pulse).

Indicators

Trigger LED:	Amber, flashes for each trigger received.
Polarity LED:	Green, two LEDs indicate the polarity of the next output pulse.
Too-Fast LED:	Amber, Lit when trigger frequency exceeds 100Hz in Alternating Polarity Mode. Results in stimulus output being disabled and FAULT condition (see below).
Out of Compliance LED:	Amber, lit when selected current not delivered.
Fault LED:	Amber, illuminated on (i) sensed over-current internally (ii) over-current to the subject or (iii) Trigger frequency “Too-fast” in alternating polarity mode. The unit is latched in this condition until reset by the Output On/Off switch being placed in the OFF position.
Power On LED:	Green, illuminated for power on

Dimensions

Size (system only):	255 x 100 x 225 mm (d x h x w).
Size (over controls and feet):	270 x 110 x 225 mm (d x h x w)
Weight:	2.1 kg (approx.)

Other Specifications

Power:	100 - 120V or 200 - 240V @ 47-63 Hz.
Power Rating:	<30 VA
Case Material:	UL94 V-0 Flame Retardant.

Important Note: This product is for research applications only. Not a medical device as defined in Regulation (EU) 2017/745 (EU MDR), Swiss Medical Devices Ordinance (MedDO, SR 812.213), or FDA 21 CFR Part 860. Not designed or intended to be used for diagnosis, treatment of disease or any other medical purposes.

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