The maximum reservoir capacitor is 4 µF. The filament is a twin horseshoe of corrugated tape. The anode is a short closed cylinder connected to, and supported by the top cap.
The main image shows the typical M-OV etched lozenge containing the Type designation.
The label shows the importance of operating a mercury vapour rectifier vertical so that the mercury is distributed correctly.
This valve carries the Osram brand of a consumer product. The anode can clearly be seen.
The top cap supports the anode and the strut is encased in glass.
The ribbon filament.
The Twin filaments at working temperature. The one on the right is hotter. Anode voltage is off. This image was taken after the filament had been hot for 20 minutes.
With anode volts applied the discharge fills the envelope.
Another view of the valve in operation. The voltage drop across the valve is very small.
The classic envelope is 50 mm in diameter and, excluding the B4 base pins, is 122 mm tall.
References: Data-sheet & 1040. Type GU50 was first introduced in 1940. See also1940 adverts.
