The very versatile PWHT01 and PWHT02 transformer

The PWHT01 and the PWHT02 transformers are designed to to meet the needs of those who experiment with valves and require a versatile transformer that is easy to configure for their needs.

This article is about how to configure the secondaries of these transformers to give you the voltages and currents you require.

The only difference between the PWHT01 and PWHT02 are the rectifier winding voltage. On the ’01 this is 5V whilst on the ’02 it is 6.3V. Both variants allow for 2A on these windings.

If you are using a thermionic rectifier then you will need to choose which of these transformer types fit the bill. The PWHT01 will be suitable for 5Y3GT or similar. The PWHT02 will be suitable for the EZ81 type of rectifier.

HT connections

Both transformer versions have two High Tension (HT) secondary windings. Both are spec’d at 250V @ 80mA.

The fact they are separate gives the user a few choices.

Parallel connection

If you need 250V but need more current than 80mA, you can parallel up the HT secondaries to give you a maximum of 250V @ 160mA, a doubling of the current.

Parallel HT secondary windings

Series connection

The two HT windings may be connected in series to give you 500V @ 80mA with a centre tap.

HT windings in series.

PWHT02 parallel low tension windings.

The PWHT02 has two low tension, LT, windings that have the same voltage. This leads to the option of placing these in parallel to give you a single high current secondary.

LT windings in parallel

Terminal protectors.

When using any high voltage transformer you must ensure that you never touch any of the high voltage terminals. That includes the primary and the secondary terminals.

We stock terminal protectors that will slide over the exposed terminals and prevent accidental touching. You can add these at the checkout when purchasing an HT01 or HT02.