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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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18th Feb 2018, 1:20 am | #21 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
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Re: Why did manufacturers use 5 volt heater rectifiers?
Couldn't you just use an EM84 in a 300mA TV heater chain, with a shunt resistor to make up the current difference?
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18th Feb 2018, 3:16 pm | #22 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Why did manufacturers use 5 volt heater rectifiers?
WOT?!
Put an extra resistor in a telly?
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18th Feb 2018, 11:19 pm | #23 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
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Re: Why did manufacturers use 5 volt heater rectifiers?
They would make fewer of the PM84, though, seeing as not all TVs would be fitted with one; so you'd expect them to be sold more expensively than an EM84 (found in almost every tape recorder), and probably by more than the cost of a resistor.
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If I have seen further than others, it is because I was standing on a pile of failed experiments. |
18th Feb 2018, 11:29 pm | #24 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,395
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Re: Why did manufacturers use 5 volt heater rectifiers?
Perhaps there was also a worry that, on switch on, the 0.2A heater of the E-eye would be proportionately harder hit as its shunt would be ohmic? Also, a bit more assemblage involved with a resistor, who knows what calculations go on with OEM quantities, T + M, favoured valve-maker deals? It might all seem arcane- but so does the 35Y4/35Z5 thing with a bulb across part of the heater to save on resistors, this time with the opposing attraction that the rectifier goes phut a little quicker when the inevitably short-lived bulb fails....
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