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Tektronix DM5120
programmable 6½-digit multimeter
Tektronix DM5120

Produced from 1989 to 1991


(all with schematics but missing most of the parts list)


Calibration Backup

(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix DM5120 is a programmable 6½-digit multimeter plug-in for the TM5000 system.

The DM5520 is a standalone version, i.e. a DM5120 in a dedicated, fan-less, mainframe based on the TM503B.

Key Specifications

Resolution ±3,029,999 counts (6½ digits) in DC Volts and Ohms, 5½ digits otherwise in fast mode
Voltage ranges 300 mV to 300 V in decade steps, DC or AC
Input Impedance (DC Volts)
  • 300 mV, 3 V: >1 GΩ
  • 30 V: 11 MΩ
  • 300 V: 10.1 MΩ
Input Impedance (AC Volts) 1 MΩ // 120 pF
Current ranges 300 μA to 3 A in decade steps, DC or AC
Resistance ranges 300 Ω to 300 MΩ in decade steps, 4-wire mode available in 300 Ω to 30 kΩ ranges
  • True RMS measurement (crest factor ≤3:1)
  • Calibration may be done manually through the front panel or via the GPIB interface.


The DM5120 shares its analog section design with the Keithley 196, minus the front/rear switch.

The instrument's internal voltage reference is based on the LM399.



Some Parts Used in the DM5120

Part Part Number(s) Class Description Used in
AD637 Monolithic integrated circuit Wideband RMS/DC converter DM5120 DM5520
LM399 Monolithic integrated circuit Heated zener reference DM5120 DM5520
Motorola 6809 156-1494-00 156-1494-01 Monolithic integrated circuit 8-bit microprocessor 2424L 2440 7D20 DM5120 DM5520
TMS9914 156-1444-00 156-1444-01 Monolithic integrated circuit GPIB controller 2221 2230 2424L 2440 4052A 4054A 021-0374-00 067-1137-99 DC5009 DC5010 DM5010 DM5120 DM5520 MI5010 SG5010 SG5030 SI5010 PS5004 PS5010

Some Parts Used in the DM5220