Stoelting 51599 Midgard 2.0 Precision Current Source 3000V Iontophoresis Used

The Stoelting Midgard is a precision current source originally designed at M.I.T. It's used for iontophoretic delivery of neural tract tracers such as HRP and tritiated amino acids, for making small lesions, and for other work that needs tightly controlled current through high-impedance pipettes. Its 3000 V compliance keeps current regulated even through very fine or partially clogged tips. This is the 2.0 version, which has touchscreen programmability and real-time status feedback.

Condition: Used / Inspected

The unit powers on with the included CUI adapter. The touchscreen responds: current setpoints (5.00 µA and 10.00 µA), Alt mode, polarity, retaining current, and on/off timing can all be adjusted. The "Over" status in one photo is the unit's out-of-range warning. It is expected when output starts with no load connected. Output was not verified under load. The housing has light cosmetic wear.

Technical Specifications

• Output current: 2–25 µA, set via touchscreen; 0.01 µA display resolution
• Compliance voltage: 3000 V
• Load current accuracy: ±0.5% at 0–200 MΩ; reproducibility 0.25%
• Modes: continuous or pulsed; on/off times variable from 0.5 to 24 s (preset 7 s on / 7 s off); timing error ±5%
• Polarity: positive or negative, with retaining current function
• Error warnings for current interrupt and out-of-range conditions
• External gating: rear-panel jack (output on while logic high)
• Output connectors: two integral high-voltage cables
• Power: 24 VDC from a universal external adapter

Included

• Stoelting Co. Digital Midgard Precision Current Source 2.0, Cat. No. 51599 (S/N 0913-19)
• Integral red and black high-voltage output leads with insulated mini clips
• CUI Inc. AC adapter, Model SDI65-24-UD (P/N SDI65-24-UD-P5): input 100–240 VAC, 50–60 Hz; output 24 VDC, 2.71 A