134

The Tektronix 134 current probe amplifier interfaces a P6019, P6020, P6021 or P6022 current probe to the voltage input of an oscilloscope. It also has a VOLTS ONLY setting of the input attenuator switch that provides a voltage gain of 125 or 50, depending on the position of the probe selector switch, with a 50 Ω input impedance. It was designed by Hans Springer. Early versions, up thru S/N 6539, had the switch positions labeled only for the P6019 & P6020 probes but these early versions are still compatible with the later P6021 & P6022 probes introduced in 1969.

Manuals – Specifications – Links – Pictures

Each 134 came with its own separate, dedicated power supply using the same Tektronix proprietary coaxial connector as that used in the Type 131s and its power supplies , but the 131 and 134 power supplies are not interchangeable. For more information on the power supplies for the Type 134, see the separate Type 015-0058-01 Power Supply page.

Key Specifications

Current Ranges	1 mA/Div to 1 A/Div, 1−2−5 (scope at 50 mV/Div)
Voltage Gain	125 in P6019/P6021 switch position
Voltage Gain	50 in P6020/P6022 switch position
Bandwidth	10 Hz to 30 MHz in P6019/P6021 x120 mode
Bandwidth	8 Hz to 54 MHz in P6020/P6022 x50 mode

Bandwidths

	P6019 + Type 134	P6019 + Passive Termination	P6021 + Type 134	P6021 + Passive Termination	P6020 + Type 134	P6020 + Passive Termination	P6022 + Type 134	P6022 + Passive Termination
Low Frequency -3 dB	≤12 Hz	≤120 Hz ≤450 Hz	≤12 Hz	≤120 Hz ≤450 Hz	≤100 Hz	≤935 Hz ≤8500 kHz	≤100 Hz	≤935 Hz ≤8500 kHz
High Frequency -3dB	≥40 MHz	≥60 MHz	≥36 MHz*	≥52 MHz*	≥70 MHz	≥200 MHz	≥54 MHz*	≥90 MHz*
Max. Continuous Current	15 Ap-p	15 Ap-p	15 Ap-p	15 Ap-p	6 Ap-p	6 Ap-p	6 Ap-p	6 Ap-p

(*These figures are system numbers and take into account the effects of a 100 MHz oscilloscope. There appears to be little or no electrical difference between the early and late families of the Tektronix current probes. P6019 & P6020 figures are from from the 1968 Tektronix catalog and do not include the oscilloscope. it's hard to understand some of them given the stated 54 MHz bandwidth of the Type 134.)

Note that in every case, the passive termination is slightly better for high frequency response, while the Type 134 improves the low frequency response.

Links

• Tek 134 @ analogdesign.be (preserved at archive.org) − photos and description

Prices

Year	1970	1974	1984	1986
Catalog price	$209	$265	$625	$625
In 2022 Dollars	$1,600	$1,600	$1,800	$1,700

Pictures

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  134 front, 1966−1969 model (P6019/P6020-only switch label)

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  134 front, 1969+ model

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  Schematic

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  latest version with wall wart PS

Measurements

Comparison of P6022 with passive termination @ 10 mA/Div (top trace) vs. P6021+134 (bottom trace). Signal is a sawtooth from a HP3325A @ 5 V_p-p into 50 Ω = 100 mA_p-p.

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  100 Hz

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  1 kHz

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  10 kHz