Steven Mark`s TPU

[BEP]

dupe

[ronotte]

@BEP,

-  The pulse transformer I'm using are doing very well their job and do provide isolation up to 2.8KV (there is a model that goes up to 5KV). They are cheap and may be found easily (cost is about 4 - 6 Euros/each).

OXFORD ELECTRICAL PRODUCTS
Pulse transformer (1:1) 3 mH, pcb mount, 2KHz - 1MHz range) model PT4 or PT42E (for 5KV isolation)

-  I'm still using my initial dotation of IRFP460 power Mosfet. In my current TPU V10-7 they are positioned inside the TPU itself and are provided with big Al heat-sink. This has been proven necessary as when you do tests often you are far from resonance ...or may make any kind of errors...so these devices with Ron < 0.4Ohm (if I remember well...) are potentially able to sink lot of current and so get burned before you (..that are looking at the scope....) are aware of it!  My suggestion is to use always current limited PS, decouple it just off the TPU, eventually insert a 2Ohm protective resistor  (..anyway this solution will have big impact on BEMF...so I don't use it).

-By  using pulse transformer (put between Gate and Source) the mosfet Gate has always a low DC path to it's own Source: this drastically eliminate any possible induction from anywere  (the mosfet constructors do strongly sufggest to use said solution....): I have seen it very well. The Mosfets themselves are put near the TPU centre.

- BEP, I'm interested about your suggestions on turn's number especially about the rules you mentioned, would you be so nice to explain it in deep or point me where to find full reports?

Here is my design:


Roberto

[ronotte]

ATTENTION TO EVERYBODY

THIS THREAD IS HIGHLY DANGEROUS AS EVERYTIME I POST SOMETHING OR I PM SOMETHING,
SOMEONE TRY TO SNEAK INTO MY COMPUTER A TROJAN

HARTI: PLEASE TRY TO STOP THIS ACTIVITY

ROBERTO

[epwpixieq-1]

NEGATIVE RESISTANCE

exerb from the Book "WAVEFORMS" - MIT Radiation Laboratory Series 1949

---- page 123
Negative-resistance Oscillators - ... Devices that exhibit negative resistance can be constructed in several ways. One of the simplest and best known methods make use of the secondary emission form the plate of a vacuum tube. An oscillator employing this type of negative resistance is called a "dynatron oscillator".  Most of the modern tubes are treated to reduce secondary emission but some older tubes exhibit this phenomenon very markedly.
----
Note that "modern" in the text references 1949 !!!

I am wondering if SM has used this knowledge when first constructed the TPU. As he stated with vacuum tubes it is easier to make it work.

Just a thought

[ronotte]

double post

HEY Harti: what's happening?

Roberto