On 10 Feb 2021, at 22:41, Stephen <email@example.com> wrote:
Telequipment that was owned by Tektronix from the late 60’s through the 1970’s, I think. They made relatively low-cost equipment targeted at the service market, rather than the higher-end engineering market targeted by Tek.
The CT71 is technically simpler than the 577 and generally light-weight construction and cheaper circuit boards, lower power (10 watts max compared to the 577’s 100 watts), and a fixed front-end with multiple device adaptors, instead of a front-end plug-in (several available) with multiple device adaptors on the 577.
The 577 has a multi-turn precision vernier for offset and switchable aid/oppose, whereas the CT71 is a standard 1-turn pot and aid-only.
The 577 is switchable 1 - 10 or 1 - 100 (?) steps; the CT71 is 1 - 10 steps only.
The 577 has single-sweep and pulsed modes, which the CT71 doesn’t have.
The 577 D1 (but not the D2 model) has analog storage, which reduces flicker with slow sweeps and allows you to easily observe curve shift over time due to heating and such, which the CT71 doesn’t have.
The 577 has a front-panel circuit breaker to cut out the collector supply if the DUT is shorted; with the CT71 you replace a fuse.