##### The 1D5 is a half wave rectifier designed for 200 mA series connected heaters as found in AC/DC radio receivers.##### The maximum reservoir capacitor is 16 µF and the effective minimum series resistance has to be 50 Ohms.##### The literature gives the UR1C as an equivalent to the 1D5, and most respects it is, but the UR1C has a 20 Volt heater at 200 mA.##### The Brimar branding.##### A closer view of the construction. The heater is a fine insulated wire that passes through the cathode eight to ten times.##### The classic envelope is 44 mm in diameter and, excluding the B5 base pins, is 100 mm tall.##### References: Data-sheet, ^{1040} & ^{1043}. Type 1D5 was first introduced in 1935. *See also* 1935 adverts. |