EHT Rectifier, Type DY86
The Mullard DY86 will be encountered in many present-day television receivers. It is a new EHT rectifier on a Noval B9A base. The heater voltage of the DY86 is 1.4V, which can be obtained from a single turn on the line output transformer. The new valve is capable of delivering a rectified current of 500μA, the peak cathode current being 40mA. This value of current is ample for modern picture tubes, and results in excellent brilliance and contrast, even in daylight.
The EHT rectifier of a television receiver must be safeguarded from the effects of over-voltage in the EHT winding of the line output transformer. The maximum peak inverse voltage of the DY86 is 22kV. An ample safety margin is thus provided for a design value of EHT voltage of 18kV.