This is the classic RF power tetrode valve for VHF and low UHF applications the 4CX250B in a contact cooled package. This exhibit is believed to be new and lacks the insulating washer that connects the cooling block to the external heatsink.

The normal B8F base is used but the socket would not have to have the forced air cooling ducts of the air cooled versions.

We have the co-axial version in the museum, the high power 3CX3000A7, as well as similar types including the lower power glass type the 4X150A.

The anode cooling block is 40 mm square and 16 mm thick. The base is 35 mm in diameter and excluding the B8F base pins and spigot the valve is 46 mm tall.

 
Pin Connections

B8F	1	2	3	4	5	6	7	8	tc
	g2	k	h	k	-	k	h	k	a

 
Absolute Maximum Operating Conditions

Tetrode	Vh	Ah	Va	Vs	mAa	Pout	freq	f.max
	6.0	2.6	1500	300	250	235	175	500

This exhibit was last updated on 18 February 2007