The 19H5 high-vacuum rectifier was originally designed by Ediswan Mazda but was supplied to the British Services by several manufacturers. Its filament rating is 4 V, 4 A.

The 19H5 is described as a very low impedance diode for charging and clamping applications in Radar.

It is believed that the filaments are in fact conventional and straight. Since the 19H5 is a high-voltage rectifier (PIV = 20,000V) it is important that each leg of the filament should be exactly coaxial with the surrounding anode (ie. equal spacing in all directions). This is why the anode structure is subdivided into 4 cylinders. The ends of each filament leg are cooled by their supports and cannot supply the same emission density as the central section. The coils seen encircling the filament supports are in fact electrostatic shields protecting the filament ends from excessive emission demand.

The output current rating of this valve in normal service is 350 mA so a full-wave pair could supply up to 20 kW at around 6 kV DC.

The base is a giant Edison screw and the anode connects to the top cap.

The construction is unusual in that the pressed sheet anodes are formed to produce four cylindrical cavities, 60 mm long and 12 mm in diameter. Each anode cavity contains a single filament. Thus the valve is in fact four rectifiers operated in parallel.

The wide glass tube envelope is 52 mm in diameter and, excluding the base pins, is 230 mm tall.

 
Absolute Maximum Operating Conditions

Rectifier	Vh	Ah
	4.0	4.0

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 02 February 2008 {find valves by name}