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420: Difference between revisions
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{{Instrument Sidebar | {{Instrument Sidebar | ||
|manufacturer=Tektronix | |manufacturer=Tektronix | ||
|class=power supply | |||
|model=420 | |model=420 | ||
|summary=high-voltage power supply | |summary=high-voltage power supply | ||
|image=420A_1.JPG | |image=420A_1.JPG | ||
|caption=420 internal view | |caption=420 internal view | ||
|introduced=1950 | |||
|introduced= | |||
|discontinued=(?) | |discontinued=(?) | ||
|manuals= | |manuals= | ||
* ''Manual needed, please add'' [[Category:Manual needed]] | * ''Manual needed, please add'' [[Category:Manual needed]] | ||
}} | }} | ||
The '''Tektronix 420''' is a high-voltage power supply used in the [[507|Type 507]] and [[517|Type 517]] scope. | The '''Tektronix 420''' is a high-voltage power supply used in the [[507|Type 507]] and [[517|Type 517]] scope. | ||
It contains transformers, rectifier tubes and filter capacitors in a separate, oil-filled enclosure with ceramic output feed-through posts. | |||
{{ | {{BeginSpecs}} | ||
{{Spec | Outputs | +20 kV @ 200 μA / –4 kV @ 700 μA, or +10 kV @ 400 μA / –4 kV @ 1.4 mA. Later models add +13.3 kV and +6.6 kV output taps (6.6 kV/3.3 kV in reduced output mode). }} | |||
{{EndSpecs}} | |||
==Internals== | ==Internals== | ||
The HV rectifiers are five [[1X2]] tubes, one for the negative and four in a Cockroft-Walton quadrupler circuit for the positive outputs. | |||
The HV rectifiers are five [[1X2]] tubes, one for the negative and four in a Cockroft-Walton | To accommodate the switchable output voltage, rectifier heaters are supplied from a second transformer inside the 420. | ||
The transformers are driven by independent oscillators using tubes located on the mainframe chassis, a [[6AU5]] for HV and a [[6AQ5]] for heaters. | The transformers are driven by independent oscillators using tubes located on the mainframe chassis, a [[6AU5]] for HV and a [[6AQ5]] for heaters. | ||
In the 517, the HV oscillator runs off an unregulated supply through its own DC series regulator with no feedback path from the HV side, only the oscillator input voltage is regulated. | In the 517, the HV oscillator runs off an unregulated supply through its own DC series regulator with no feedback path from the HV side, only the oscillator input voltage is regulated. | ||
The 507 HV oscillator, supplied from the regulated +225 V rail, takes feedback from the negative HV output.. | The 507 HV oscillator, supplied from the regulated +225 V rail, takes feedback from the negative HV output.. | ||
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==Pictures== | ==Pictures== | ||
<gallery> | <gallery> | ||
Tek 420 hvps.png|Entry in 1950 Catalog | Tek 420 hvps.png | Entry in 1950 Catalog | ||
Tek 517 420 hv.jpg | later model 420 (with 13 and 6 kV outputs) in a [[517]] | |||
Tek 517 420 hv.jpg | later model 420 (with 13 and 6 kV outputs) in a [[517]] | Tek_517_hvps2.png | Schematic of 420 (to the right of and including the transformers) in the Type 517 | ||
420A_1.JPG| | Tek_507_crt_circuit.png | Schematic of 420 (between the dashed lines) in the Type 517 | ||
420A_2.JPG| | 420A_1.JPG | Five [[1X2]] high voltage rectifier tubes inside a 420A | ||
420A_2.JPG | HV multiplier, "[[black beauty]]" capacitors inside a 420A | |||
</gallery> | </gallery> | ||