Tube filament supply - npn switches

140

01:07:22

This circuit converts 12_Vdc to 6.3_Vdc to heat radio tube's filaments. The special features include synchronous switching of two npn transistors. Replacing a diode in the classical scheme by transistor (right) significantly reduces the losses. Switching takes the signal from the driver circuit with a gradual increase in the duty cycle and hence the gradual heating of the radio tubes (Soft heating of tube filament).

Данная схема преобразует постоянное напряжение 12_В в постоянное напряжение накала радиоламп 6.3_В. К особенностям можно отнести синхронную коммутацию двумя n-p-n транзисторами. Замена диода в классической схеме на транзистор (справа) заметно снижает потери. Коммутация происходит сигналом от схемы драйвера с плавным увеличением скважности и, значит, плавным нагревом нитей канала радиоламп. 

published 11 years ago

faceblast

11 years ago

that's a lot of power to run the heaters, how many tubes are heating with it

alexmayorov

11 years ago

For load resistance 1 Ohm current is about 6 Ampere. It means that 3-4 tubes can be heated.

hurz

10 years ago

I would still prefer the classical method http://everycircuit.com/circuit/4957084037152768

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