The VT13C (later renamed the CV1562) is a directly heated transmitting triode for use up to 6 MHz. The VT signifies the old RAF service code pre 1941.
The maker's name, Type designation and old stores code of 10A/7510. The 5.6 is the filament voltage and the 30 denotes the maximum anode dissipation.
The construction is of a bright horizontally mounted anode cylinder with a helical control grid and single strand filament.
The Air Ministry AM and crown.
Microscope image of the helical grid with a single support rod on the left. The single filament strand runs through the centre. The curve on the far left is the cylindrical anode.
The balloon envelope is 55 mm in diameter and, excluding the L4 base pins, is 90 mm tall.
