Almost every piece of industrial, military, and commercial electronic equipment incorporates a source of stable voltage. Mullard gas-filled stabilisers and voltage reference tubes such as the 90C1 and 85A2 are widely used in such equipments because of their extremely long life, freedom from voltage jumps, and close tolerance burning voltages. Samples of Special Quality versions of these tubes are now being made available by the Communications and Industrial Valve Department of Mullard Ltd. These combine the good qualities of normal types with the ability to operate satisfactorily under severe conditions of shock and vibration such as are encountered in aircraft, ships, vehicles, and in industry. They are tested to withstand impacts of 500g and vibrations of 6g at 175 cycles per second.
The new tubes are electrically equivalent to the 85A2, the 90C1, and the 150B2. They are available in two forms, one with pins and one with flying leads. Flying leads are desirable because, since they can be soldered firmly in place, variations in contact resistance such as are encountered when plug-in types are subjected to vibration are eliminated. Such variations give rise to noise and minute voltage fluctuations which degrade the high performance of a voltage reference tube. The fact that replacement is more difficult mechanically than with plug-in types is of little importance in view of the long life of these tubes.
The type numbers of the new Special Quality stabilisers are as follows.
The M8098 and M8142 are electrical equivalents of the Mullard 85A2 voltage reference tube (CV449). M8098 has a B7G base and M8142 (CV4054) has flying leads.
The M8206 and M8207 are pin base and flying lead base equivalents respectively of the Mullard 90C1 voltage stabiliser.
The M8163 and M8208 are pin base and flying lead base equivalents of the Mullard 150B2 voltage stabiliser (CV2225).
Full scale production of these important new additions to the Mullard special quality range will commence early in 1955.