The Tektronix Type 131 is a current probe amplifier used only with the P6016 current probe. Type 131s were never given serial numbers, instead, they were produced chronologically in "Models." Models 1 thru 3 looked alike, while Model 4 got a redesigned enclosure like that used later by the Type 134.

Tektronix Type 131
Current Probe Amplifier
Type 131 Model 4 Current Probe Amplifier

Produced from 1960 to (?)

Manuals
(All manuals in PDF format unless noted otherwise)

Key Specifications

Sensitivity 1 mA/Div to 1 A/Div, 1−2−5 (scope input fixed at 50 mV/Div)
Noise 0.1 mAp-p
Risetime 20 ns (eq. 17 MHz −3 dB bandwidth)
Lower frequency limit 50 Hz
Delay time 32 ns typ.

(all specifications are overall values including the P6016 probe)

Connectors

All models of the 131 use a BNC input connector.

The vast majority of 131s, including all the Models 1 thru 3, have a UHF output connector. 131 Model 4s with UHF outputs were Tektronix #015-0029-00.

A few very late 131 Model 4s were supplied with a locking BNC output connector, as Tektronix #015-0050-00.

Internals

All four Type 131 models used PNP transistors, thus requiring a negative power source. Models 1 thru 3 were hard-wired to their separate minus ~19 V power supplies, while Model 4 got a power supply, 015-027, for 115 VAC, with a proprietary Tektronix coaxial connector. While the Type 134 uses the same coaxial power supply connector, the power supplies are not interchangeable — Type 131 Model 4 will only work with the correct 015-027 power supply.

See the 015-027 power supply page for more information.

Pictures