Totem-pole gate driver VS Active pull down VS Fast Fet turn off

[waltr]

Tests I've done, signal strength proportional to peak current. If current is reduced to half, how much increase in pulse rate should be needed to get S/N back to where it was before current was decreased.

I increase series resistor (decrease peak coil current) just enough to prevent MOSFET avalanche for cleanest sampled signal.

Well, there's duty cycle as well, it gets rather complicated The way to approach such a calculation is of course to use calculus. Then compare actual measured results.
There is no doubt in my mind that we are dealing with a collapsing electromagnetic field and as such one should be careful in not underestimating it's inherent effect. It may be non linear.

No simple calculations since Peak current vs pulse rate vs integrator values vs sampling time are none linear.

Same with doing GB sampling.

[dbanner]

Well, there's duty cycle as well, it gets rather complicated The way to approach such a calculation is of course to use calculus. Then compare actual measured results.
There is no doubt in my mind that we are dealing with a collapsing electromagnetic field and as such one should be careful in not underestimating it's inherent effect. It may be non linear.

[green]

Yes, decrease peak coil current and increase pulse rate is a goo way to go.

Tests I've done, signal strength proportional to peak current. If current is reduced to half, how much increase in pulse rate should be needed to get S/N back to where it was before current was decreased.

[dbanner]

BTW waltr, you forgot the d at the end of goo..

Well, after much bemusement, I finally have a circuit that even l could be proud of. Can't see the nitty gritty, but at least it didn't go into meltdown.

I pause, I'm reminded of those experimental scientists, they had surely earned their keep. Keep up the good work guys, now only if I can analyze this waveform....

[waltr]

Yes, decrease peak coil current and increase pulse rate is a goo way to go.

[Ferric Toes]

This has been some good reading.

So keeping MOSFET out of avalanche is a good thing.
Another way to do this is to reduce the peak coil current with a series resistor. This also decreases the coil Tau and allows longer TX on pulse (good for high conductive targets).

I ended up adding 10 Ohms in series with the coil on the Hammer-head I built. Without the resistor the detection was not quite stable.
Later did distance tests and found that detection distance didn't decrease with lower coil current. Possible due to MOSFET going into avalanche and first sample being cleaner.

Hi Waltr, Yes, that is a good way. I have also wound coils with thinner wire to decrease the coil Tau. The coil I have been using for the tests reported in this thread is wound with 1.0/0.2 wire, PTFE insulated, and the resistance works out, without cable, about 5ohms. With cable is is 5.8ohms. Adding 10ohms in series on the live side reduced the flyback from 600V to 300V and nice flat top Tx current pulse for the last 200uS of a 300uS total length. What I have done previously with such an arrangement, is increase the pulse repetition rate to end up with the same current draw as it was without the additional series resistance. This can help to make up for the lower S/N due to the reduced Tx current amplitude.

The avalanche mode in a Mosfet appears to be similar to that of a zener diode, which is well known to be noisy. I wonder if the noise stops immediately the device exits the avalanche region, or does it continue for a while?

Eric.

[dbanner]

Yeah, biorobots indeed. Those were great men willing to give their lives to save, well, probably the entire European continent. Now we say loonie tunes in power across Europe and you have to wonder
I'll take my dose of Boris Johnson any day, as crazy as that seems, than to live under any psuedo socialist super state. We saw how that ends.

Anyways, back to the topic please.

I'm breadboarding a front end pi circuit and guess what, the damn Chinese breadboard is a trap. Sheesh, I blew up two transistors before I realized the bus ain't no bus at all!!

I'll use pidgin..... Cheap Ting no good, shaft you in Bam Bam!!!

[kt315]

yup, they were just biorobots, living biorobots... someone did want to crash USSR out and got that.

[dbanner]

Hi kt, yeah. Hats off to those who gave their lives

[kt315]

yes, those guys did the series in our sity. Ignalina's two reactors are same types. they are closed now both.
but they made the movie not on the station, but in layout for learning of staffs. it is faraway from IAES and the city.
all town plans they found/did in Vilnius. so you see in reality just Lithuania, not Ukraina.

https://www.kelioniulaikas.lt/kelion...ieska-visagine
Want to know what happened at the Chernobyl nuclear power plant?
You will find the answers to this and other relevant questions by visiting Visaginas, where the Ignalina Nuclear Power Plant, which operated until the end of 2009 and has supplied electricity to the Baltic States, is located.
Follllowing in the footsteps of the HBO series Chernobyl filmed in Lithuania, we will see an identical reactor, the explosion of which shocked the world, and by controlling the power plant simulator we will feel as if we are the owners of a functioning power plant.