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Tuesday, August 3, 2021

CONTINUITY: Vacuum Tube Computer Part 15: Soft-Start Power On Circuit

With the project about half done and already employing around 90 vacuum tubes, it's time to deal with the massive in-rush of current when power is applied to all of those cold heaters at once. (Vacuum tube filaments have low resistance when cold, which rises as they reach operating temperature.) A clever circuit which uses the filament warm-up of gas-filled thyratron tubes as a time delay comes to the rescue.

Posted at August 3, 2021 10:40