221: Difference between revisions

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* [http://manoman.sqhill.com/pdf/tek-221.pdf Tektronix 221 Manual (PDF)]
* [http://manoman.sqhill.com/pdf/tek-221.pdf Tektronix 221 Manual (PDF)]
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Image:Tek 221 1.jpg
Image:Tek 221 right.jpg
Image:Tek 221 probe.jpg
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Revision as of 17:52, 9 May 2011

The Tektronix Type 221 is a miniature 5MHz analog scope introduced in 1973. It has a switching power supply and built-in rechargeable batteries (which are a maintenance issue). It has a transformer-coupled trigger circuit which would seem to preclude DC level-based triggering. The trigger circuit uses a 1N3713 1mA tunnel diode. The vertical output amplifier that drives the CRT plates is two opamps made from discrete transistors. One drives the top deflection plate and the other drives the bottom plate.