213

Manuals – Specifications – Links – Pictures

The Tektronix 213 is a miniature portable oscilloscope introduced in 1975. It combines a 3½-digit DMM and a 1 MHz single channel scope in one unit. The maximum sweep rate is 0.4 μs/div with ×10 sweep magnifier.

The 213 provides true RMS voltage and current measurements. It is battery or AC line powered.

The 213 "Miniscope" was developed by a group led by Dave Allen, including John Pace, Gordon Meigs, Wendell Damm, Jim Knowlton (power supply) and others.

Key Specifications

	— Multimeter Section —
DC Volts	0.1 V to 1000 V, Input Resistance: 10 MΩ Accuracy, 0.1 V & 1 V: ±0.1%, ±3 counts; 10 V & 100 V: ±0.15%, ±1 count; 1000 V: ±0.2%, ±1 count
True RMS Volts	DC Volts
DC Current	0.1 to 1000 mA Accuracy: 0.1 mA: ±0.5%, ±3 counts; 1 mA – 1000 mA: ±0.25%, ±3 counts
True RMS Current	0.1 to 1000 mA Accuracy, 0.1 mA: ±2.5%, ±5 counts (DC); ±1.5%, ±5 counts (40 Hz – 4 kHz); ±4.5%, ±5 counts (4 kHz − 40 kHz); 1 mA – 1000 mA: ±2.5%, ±5 counts (DC); ±1.5%, ±5 counts (40 Hz – 4 kHz); ±3.5%,±5 counts (4 kHz − 40 kHz)
Current range input resistance	0.1 mA: 1000 Ω; 1 mA: 100 Ω; 10 mA: 10.2 Ω; 100 mA: 1.2 Ω; 1000 mA: 0.3 Ω
Resistance	1 KΩ: ±0.5%, ±3 counts; 10 KΩ – 1 MΩ: ±0.5%, ±1 count; 10 MΩ: ±1%, ±1 count
	— Oscilloscope Section —
Voltage ranges	5 mV/Div to – 100 V/Div, ±3%
Bandwidth (Voltage)	DC – 1 MHz (at 10 mV/Div and below, 400 kHz)
Current ranges	5 µA/Div to 100 mA/Div, ±3%
Bandwidth (Current)	DC – 200 kHz (5 µA/Div – 10 μA/Div); DC – 400 kHz (20 μA/Div – 200 mA/Div)
Input resistance	10 MΩ // 150 pF (5 mV/Div – 1 V/Div), 100 pF (2 V/Div to – 100 V/Div)
Rise time	875 ns (5 mV/Div – 10 mV/Div); 350 ns (20 mV/Div – 100 V/Div)
Sweep	500 ms/Div – 2 µs/Div, ±5% (magnified or unmagnified)
Batteries	2 × “D” NiCd cells
Operating time	3.5 hours typical at maximum intensity after full charge cycle
Charge time	16 h
Mains power	90 – 136 VAC. 48 – 62 Hz (Option 1: 180 – 250 VDC. or 180 – 250 VAC, 48 – 62 Hz)
Power consumption	Less than 8 watts

Links

• David Allen, The Birth of the Miniscope @ VintageTek.org
• EEVblog #628 – Tektronix 213 Vintage Portable Oscilloscope Teardown Video and Photo Set
• Tektronix 213 DMM Repair Progress video

Documents Referencing 213

Document	Class	Title	Authors	Year	Links
Tekscope 1975 V7 N1.pdf	Article	A Hand-held DMMiniscope	Dave Allen	1975	213

Prices

Year	1976	1977	1980	1982	1986
Catalog Price	$1,200	$1,425	$1,750	$2,100	$2,830
In 2023 Dollars	$6,500	$7,200	$6,500	$6,700	$7,900

Internals

The 213 makes use of two Tek-made custom chips, the 155-0048-01 trigger sweep circuit, and the 155-0114-00 7-segment character generator in the DVM circuit. In addition, it includes some standard opamps (741, 324) and a 4-digit decimal counter (Mostek MK5007).

Pictures

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  Tek 213 front

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  In DMM mode

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  Tek 214 (top), 213 (center) and 211 (bottom) stacked

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  Tek 213 size comparison with 500 series plug-in bay (in a 585)

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  213 with pouch

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  right side

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  without covers, bottom/left

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  without covers, left

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  without covers, top

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  without covers, operating, top/right

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  213_amplifier_board

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  213_bottom_view

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  213_closeup_CRT_drive

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  Plastic case halves

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  Original battery, corroded

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  In DMM mode

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  In scope mode

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  Catalog image, front

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  Catalog image, side

Schematics

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  Attenuator and Input Amplifier Schematic

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  GM and RMS Converter Schematic

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  Battery Charger and Power Supply Schematic

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  HV and CRT Schematic

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  A-D Converter and Character Generator Schematic