PT4 @ The Valve Museum

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PT4

Sensibly equivalent^¶ to:

42MP/Pen 7A3 A70C A70D AC/Z AC2/Pen APP4B CV1181 KT41 N41 Pen4VB PenA4

Extras ▼

Osram Photographic Donations Other PT4 exhibits

The Osram PT4 is a directly heated output pentode that was introduced in 1931 and could be used in AC or DC mains sets.

The MPT4 would have a greater output and is indirectly heated.

The remains of the Osram brand label.

Looking up from the pinch.

Thanks to Mike Edwards for the pictures and information that this valve came from a 1932 Kolster Brandes KB321 wireless set.

The classic envelope is mm in diameter, and excluding the B5 base pins is mm tall.

References: Data-sheet, ¹⁰⁴⁰ & ¹⁰⁴³. Type PT4 was first introduced in 1931. See also 1931 adverts.

Pin Connections

B5	1	2	3	4	5
	a	g1	f(-),g3	f(+)	g2

Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	rk	rl	Pout	D
	4.0	1.0	250	250	-16.0	32.5	7.0	42,000	2.85	420	7,500	2.0W	10%

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated October 06, 2020.

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