20D1 @ The Valve Museum

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20D1

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Valves and their Habits

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Mazda The Communications & Electronics Museum Trust Other 20D1 exhibits

The 20D1 is a double signal diode with separate cathodes. Possible uses would be demodulation of signal and AGC voltages. The 200 mA heater requirement indicates universal mains sets with series heater chains.

Our other 20D1 has the newer style of lettering.

One diode section, with the radiating area much larger than the working central hollow cylinder.

The central plate is the electrostatic screen.

The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 46 mm tall.

References: Data-sheet & ¹⁰⁴⁰. Type 20D1 was first introduced in 1949. See also 1949 adverts.

Pin Connections

B7G	1	2	3	4	5	6	7
	k(1)	a(2)	h	h	k(2)	s	a(1)

Absolute Maximum Operating Conditions^¶

Diode	Vh	Ah	Va	mAa
	9.5	0.2	175	9

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated September 11, 2013.

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