81A

Tektronix 81A
plug-in adapter Type 81A Compatible with 580-series scopes Produced from 1967 to 1972 Manuals Tektronix Type 81A Manual Factory Calibration Procedures Type 81A FCP (Manuals are OCRed PDF files unless noted otherwise)

Manuals – Specifications – Links – Pictures

The Tektronix Type 81A is a plug-in adapter that allows letter-series and 1-series plug-ins to be used in 580-series scopes.

It superseded the earlier Type 81. Type 81A is solid-state and has a bandwidth of 50 MHz vs. 33 MHz in the older, tube-based 81.

The 81A was designed by Bill DeVey. Bill DeVey had also designed the 81. The 581 and 585 first appeared in the May 1959 catalog. John Gates could not have designed it because he did not join Tektronix until about March in 1960, while the 81 would have been nearly essential for the 581 and 585 design by John Kobbe.

Key Specifications

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Internals

The letter-series plug-in drives the input stage of the Type 81A which is high impedance – a FET source follower pair – so that the plug-in sees conditions similar to the input of a 530-, 540-, or 550-series scope. The second stage is a cascoded BJT amplifier.

Type 81A also terminates the grid line of the distributed vertical amplifier (delay line driver).

The Type 81A has a spoiler switch.