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434: Difference between revisions
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An option for a tube with higher sensitivity at high writing speeds was available (OPT. 01). | An option for a tube with higher sensitivity at high writing speeds was available (OPT. 01). | ||
The signal passes through rotary cam-operated input attenuators, then a JFET source-follower buffer | The signal passes through rotary cam-operated input attenuators, then passes through an input amplifier | ||
that is on a separate small board. The input amplifier contains a JFET source-follower buffer | |||
that uses a [[2N5911|2N5911A]] (Tektronix part number 151-1032-00) biased with a drain current of 12.5mA | that uses a [[2N5911|2N5911A]] (Tektronix part number 151-1032-00) biased with a drain current of 12.5mA | ||
and Vgs of -0.26V. | and Vgs of -0.26V. The input amplifier has unity gain, high input impedance, and an output impedance of | ||
about 120 ohms. The input amplifier drives a Tek-made differential amplifier chip, part number [[155-0050-01]]. | |||
* [http://w140.com/tektronix_434_service.pdf Tektronix 434 Manual sn 500,000 and up (complete, PDF)] | * [http://w140.com/tektronix_434_service.pdf Tektronix 434 Manual sn 500,000 and up (complete, PDF)] | ||