Tripler (voltage multiplier)

A tripler is device used to multiply an ac voltage by 3. It is constructed from a chain of diodes and capacitors.

A tripler is the most popular type of voltage multiplier, with multipliers able to multiply to various ratios of input voltage. These are also known as Cockroft-Walton multipliers.

The output voltage of a tripler is in practice well below 3x peak input voltage due to their high impedance, caused in part by the fact that as each capacitor in the chain supplies power to the next, it partially discharges, losing voltage doing so.

Uses

The biggest use for triplers has been the boosting of output voltage from a winding in a TV flyback transformer (LOPT) in order to supply EHT (Extra High Tension Voltage), typically 19-25kV, to the final anode of cathode ray tube in a color television receiver. With the introduction of diode split flyback transformers in the 1970s they have largely fallen into disuse, leading to a more reliable receiver designs, devoid of a component which once accounted for a significant amount of failures.

TV triplers became known for their susceptibility to dampness. Even short exposures to humid air caused many failures.

A lot of 1970s TV sets used open triplers, and the individual diode sticks could be replaced if they failed. Repair shops came to know stormy conditions as a regular cause of tripler failures. In the 1980s, sets normally had sealed potted triplers, with much better resistance to bad weather. However they would still often fail if exposed to damp air.

Triplers are still used in high voltage supplies for copiers, laser printers, insect electrocutors, etc.

ee also

*Voltage multiplier
*Flyback transformer