DS7A / DS7AH

Digitimer

High Voltage Constant Current Electrical Stimulator

The Digitimer DS7A and DS7AH are high-voltage, constant-current stimulators designed for transcutaneous electrical stimulation of peripheral nerves and muscles. Both stimulators provide precise and safe single-pulse electrical stimulation and are widely used in human neurophysiology research and intraoperative monitoring.

The DS7A is ideally suited for general nerve and muscle stimulation tasks and supports pulse durations up to 2 ms, making it a versatile tool for cognitive neuroscience, pain studies, and reflex investigations. The DS7AH, on the other hand, is a high-current variant designed specifically for demanding applications requiring up to 1000 mA of current, such as deep nerve or large muscle stimulation.

Both devices deliver isolated stimulation with a compliance voltage of up to 400V, and feature TTL control inputs, making them ideal for integration into automated lab setups.

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DS7A vs DS7AH – Model Differences

While both the DS7A and DS7AH share the same form factor and safety certifications, there are important differences in output capabilities and intended applications:

Feature	DS7A	DS7AH
Max Output Current	100 mA	1000 mA (1 A)
Pulse Duration Range	50 µs – 2000 µs	50 µs – 200 µs
Max Pulse Energy	<50 mJ	<50 mJ
Compliance Voltage	400 V	400 V
Applications	General peripheral nerve/muscle stimulation	Deep nerve and large muscle stimulation

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Key Features

High voltage (400 V), constant current stimulation
DS7A: Up to 100 mA current output
DS7AH: Up to 1000 mA (1 A) current output
Short-duration single pulses (50 µs to 2 ms for DS7A, up to 200 µs for DS7AH)
Front-panel amplitude control with lockout function
Manual trigger button and BNC input for external TTL triggering
Bipolar output via safety DIN 42802-connector
Compatible with Digitimer isolation units and accessories
CE marked & FDA 510(k) cleared

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Applications

Transcutaneous electrical nerve stimulation (TENS)
Evoked potential research (e.g. F-waves, H-reflexes)
Pain and nociception studies
Startle response studies
Intraoperative monitoring
Conditioning studies and paired-pulse paradigms
High-current stimulation for large or deep muscles (DS7AH)

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Specification	DS7A	DS7AH
Output Type	Isolated Constant Current	Isolated Constant Current
Pulse Polarity	Three position toggle switch +ve, -ve and alternating polarity options	Three position toggle switch +ve, -ve and alternating polarity options
Output Current Range	0 – 99.9 mA (selected by 10 turn dial and x1/x10 switch)	0 – 999.9 mA (selected by 10 turn dial and x1/x10 switch)
Pulse Duration	50 µs, 100 µs, 200 µs, 500 µs, 1000 µs, 2000 µs	50 µs, 100 µs, 200 µs
Compliance Voltage	Continuously variable from 100V to 400V	Continuously variable from 100V to 400V
Triggering	Manual button or external TTL pulse	Manual button or external TTL pulse
Connections	4mm shrouded, touchproof sockets (red and black) on 3/4" centres	4mm shrouded, touchproof sockets (red and black) on 3/4" centres
Dimensions	225 × 100 × 255 mm	225 × 100 × 255 mm
Weight	Approx. 3kg	Approx. 3kg
Certifications	CE, FDA 510(k)	CE, FDA 510(k)

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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