What is an "HT" transformer?

Discussion in 'General Electronics Chat' started by ianderso, Apr 26, 2006.

  1. ianderso

    ianderso Thread Starter New Member

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    While I've built many 9VDC solid-state projects (think effects for guitar players), I'm starting to test the waters on making some tube-driven devices. I was looking over some old schematics and kept seeing a reference to an "HT" attached to the plates of the tubes (usually ECC83s or similar) in the schems. I know it's a transformer reference, but what, exactly, does the "HT" mean?

    Thanks,
    IZA
  2. Papabravo

    Papabravo AAC Fanatic!

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    I think it might mean "High Tension". This arcane terminology still shows up in high voltage circuits. It generally takes a step-up transformer to go from 120VAC to a typical +300VDC plate supply.
  3. windoze killa

    windoze killa Distinguished Member

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    You are correct. HT means High Tension and EHT is Extra High Tension. EHT transformers are generally in the KV range.

    HT transformers can have an O/P anywhere from about 100V to about 1KV. Some are multi tapped to provide voltages for the screen grid and supressor grid as well as the plate supply.
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