U21 @ The Valve Museum

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U21

Sensibly equivalent^¶ to:

CV3751 SU2150

Extras ▼

Mazda The Hammersmith Collection

The Mazda U21 is a low current EHT rectifier as used in CRT supplies.

The anode is held firmly in place by supports embedded in the glass rods moulded into the pinch.

The cathode is an oxide coated tube with the heater running inside. The cathode is connected to one side of the heater.

The most successful implementation of this EHT rectifier specification can be seen in the Cossor SU2150.

The classic envelope is 39 mm in diameter, and excluding the B4 base pins is 100 mm tall.

References: Data-sheet & ¹⁰⁴⁰. Type U21 was first introduced in 1937. See also 1937 adverts.

Pin Connections

B4	1	2	3	4	tc
	nc	nc	f	f	a

Absolute Maximum Operating Conditions^¶

Rectifier	Vh	Ah	Va	mAa
	2.0	1.85	4,500	5

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated January 05, 2022.

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