The 3B/240M is a small VHF transmitting triode. The drive required for full output is 2.5 Watts and the maximum grid current is 35 mA. This suggests the design use is class C and so would be used for AM and CW transmitters.

The side view reveals the two independent anode fin arrangements with the cathode assembly in the centre.

The use of multiple grid and cathode connections is to reduce capacitances and thus achieve the 200 MHz frequency.

The wide glass tube envelope is 27 mm in diameter and, excluding the B8B base pins, is 62 mm tall.

 
Pin Connections

B8B	1	2	3	4	5	6	7	8	tc
	h	k	g1	g1	g1	g1	k	h	a

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	Pdiss	Pout	freq
	6.3	1.1	300	-10.0	90	15W	16W	200 MHz

This exhibit was last updated on 24 July 2005