Pulse Induction History and Theory

[Ferric Toes]

Thyratrons can be found on Ebay--I bought one for experimentation. Advantages: very low on resistance, can handle very high currents and can tolerate high voltage without breakdown, in contrast to semiconductor devices.

Prospector_Al

In 1975 John Alldred and I tried a 2N5574 TRIAC device for a 1/2 sine transmitter. Worked fine and a pity we did not pursue it further.

When I worked at Mullards there was a thyratron device that pulsed current through a 1/2in square copper bar to magnetize magnetron magnets. Hate to think what the peak current was but the bar was hot after just two or three pulses. The pulser was in a room of its own and you could audibly hear the thump of the current when the discharge button was pushed.

Eric.

[Prospector_Al]

Here are some further comments, corrections, and observations by John Alldred, who worked for me in the 1970's.

Eric.

[ATTACH]22392[/ATTACH]

Thyratrons can be found on Ebay--I bought one for experimentation. Advantages: very low on resistance, can handle very high currents and can tolerate high voltage without breakdown, in contrast to semiconductor devices.

Prospector_Al

[Thomas]

I really enjoy reading your pdf articles, keep'em coming. Thanks!

[Ferric Toes]

Utilisation of Magnetic Viscosity Effects in Soils for Archaeological Prospection

1966 paper on the application of PI to location of buried pits, ditches, etc.

Eric.

Colani 1966 001.pdf

[Ferric Toes]

Eddy Current Method for Measuring the Resistivity of Metals. 1959.

A paper from 1959 which is relevant to PI.

Eric.

Bean et al001.pdf

[Ferric Toes]

Here is the next installment, although going backwards in time to 1955. This is the paper by Westcott that Johnson cites in his work.

Eric.

Westcott002.pdf

[Ferric Toes]

Damn it!, where can I get a thyratron? *LOL*
(No, I'm not going to build a thermo nuclear bomb igniter with it.)

Thanks Eric. Very interesting.
Aziz

You don't need anything as high tech as a thyratron, just use an ordinary iron clad mains switch. It was good enough for Johnson.

[Aziz]

Damn it!, where can I get a thyratron? *LOL*
(No, I'm not going to build a thermo nuclear bomb igniter with it.)

Thanks Eric. Very interesting.
Aziz

[Ferric Toes]

The comments on the margin are also very informative. Thanks.

Here are some further comments, corrections, and observations by John Alldred, who worked for me in the 1970's.

Eric.

John A's Comments001.pdf

[Davor]

The comments on the margin are also very informative. Thanks.