The 2D13C is an indirectly heated double diode for radio receivers. Diode one is for AGC rectification and diode two is for signal demodulation. The 200 mA heater requirement is for use in a heather chain across the mains supply in universal AC or DC sets.

The side view showing the pinch and cylinder.

The screen cylinder and the two rod anodes. The cathode is strapped to the cylinder. The second inner rod on the left has no visible connection. The matching inner rod on the right appears below the bottom mica.

The lower electrodes.

The close-up view into the outer cylinder. The multiple heater strands are easy to see.

The classic envelope is 38 mm in diameter, and excluding the B5 base pins is 90 mm tall.

 
Pin Connections

B5	1	2	3	4	5
	a(d2)	a(d1)	h	h	k

 
Absolute Maximum Operating Conditions

Diode	Vh	Ah	Va	mAa
	13.0	0.2	200	0.8

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 23 August 2008