The UR1 is a half wave power rectifier on a continental Ct8 base and dates from the early to mid 1930s. The data manuals from 1950 only list the UR1C on a British B5 base. The Ct8 was not popular in the UK in spite of achieving good sales in Europe.

The anode is made of mesh and the cathode is quite long compared to sensibly equivalent valves such as the 1D5.

The series resistance has to be a minimum of 125 Ohms for this rectifier and the reservoir capacitor should not exceed 32 µF.

Mullard replaced this rectifier in 1939 with the CY1 (Ct8) and CY31 (IO).

The details of the valve are etched into the top of the envelope.

The balloon envelope is 36 mm in diameter and, excluding the Ct8 base pins, is 88 mm tall.

 
Absolute Maximum Operating Conditions

Rectifier	Vh	Ah	Va	mAa
	20.0	0.2	250	75

This exhibit was last updated on 02 December 2007