What is an "HT" transformer?

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

  1. ianderso

    ianderso Thread Starter New Member

    Apr 26, 2006
    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?

  2. Papabravo

    Papabravo AAC Fanatic!

    Feb 24, 2006
    Michigan, USA (GMT-5)
    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

    Feb 23, 2006
    Melbourne Australia
    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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