1x TV7D/U TESTED NOS+Bogey+ RCA Radiotron UX-874 Globe Balloon Tube *PURPLE GLOW

Description

The sale is for 1x ONE TUBE / VALVE / LAMP
(1) RCA Radiotron UX-874 Tube
Calibrated TV7D/U TESTED Very Strong at meter rating of 120+ (see pics, 120=1,500 Gm)
where minimum Good (60-65% tube life) is a meter reading of 40 = 500 Gm.
Condition:
Could be NOS Unused or just Lightly Used, No original box, TV7D/U Tested Very Strong
NOS+ Bogey+, UX-4 Clean Pins, Glass & Internals -
Glows Bright Purple
The tube was used commercially starting in late 1927 into the 1930's.
This tube was used as a Single Voltage Regulator in Power Supply's originally designed for
RCA Type 104 AMPLIFIED SPEAKERS .
This tube type will glow Blue to Deep Blue to a rich Purple color when powered on
at the correct voltage and current. The
Gas Vapor inside the glass is either Neon/Mercury or
Argon gas. This tube will be packaged very well for safe shipping.
Voltage Regulator
The Globe / Balloon UX-874 Vacuum Tube was developed by Westinghouse & General Electric iover1924-1927.In late 1927 RCA started production. It has a 150V stabilized voltage at 10 to 50mA and requires a four pin UX-Base socket.
Regulator
Maximum Supply Voltage ........................ 125 V
Regulated Voltage ............................. 90 V
Maximum Current ............................... 50 mA
Minimum Current ............................... 10 mA
Voltage regulator 90 Volt (ignition 125 V), 10 - 50 mA,
Tube Info:
Country:
United States of America (USA)
Brand:  RCA Victor (RCA Radiotron) NY,NY
Developer: GE for Brand RCA-Radiotron
Tube type: Voltage Regulator, single Power Supply
Identical to
UX-874
= CX374 = 38274 = SE-3918 = CV643
Base
UX-Base (4 Pins (2 thick, USA 1924, UX)
Was used by
Radio/Early Amplified RCA speakers
Description
Late in 1924 experiments began at the Westinghouse laboratories on designing a neon gas voltage regulator tube. Work started on development of this tube in March 1925. the tube became available in the following year but it was plagued with difficulties. Research into these problems was transferred to the GE laboratories in March 1927. It was not used in any great extent commercially. The cylinder element was connected to one base filament pin and the other element was connected to the grid pin. With this connection, the battery eliminator cannot be turned on until the tube is inserted in the socket. The tube was originally designed for use with the RCA type 104 amplified speaker.
Voltage regulator 90 Volt (ignition 125 V), 10 - 50 mA,
Dimensions (WHD)
incl. pins / tip
Thanks for Looking!
x 137 x 54 mm / x 5.39 x 2.13 inc