4 X TRIODE VALVES, circa 1920

Four Wireless Valves from the 1920's. All are for battery receivers with there type and maker listed below: -
A= Dario Resistron Bivolt Made in France in around 1928. A Triode with a 1.8 Volt Heater and an Anode voltage of 160 Volts. This valve enabled sets to be built without Transformer coupling between the stages; a resistor and a capacitor were used instead.
B= Dario Power Bivolt Made in France. A power output Triode of around 1930 with a 2-volt Heater.

Bruce Hammond Collection.
C= Osram DE2 Valve of 1926. A Dull Emitter LF Triode with a 1.8 Volt Heater.
D= Mullard D3 with a double green ring around the glass, identifying it as a Dull Emitter LF Triode of 1926 with a 2 Volt Heater and an Anode voltage of 50 to 125 Volts.

A1733