545

The Tektronix 545 is a 33MHz scope that takes a letter-series or 1-series vertical plug-in. It has two timebases, which allows delayed triggering. There was the 545, then the 545A, and then the 545B. The 545A improved the control ergonomics significantly but did not embody any major design changes. The 545 has a six stage differential distributed vertical output amplifier made of twelve 6DK6 tubes. The 545B has a partly solid-state, non-distributed vertical output section and uses the same CRT as the 544, 546, and 547. All versions of 545 use Schmitt trigger circuits for triggering the sweeps. The trigger circuit was made with a 6DJ8 tube in the original 545 and with NPN transistors in the 545B. The 547 replaced the 545.

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  545B signal path

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  545A block diagram