Hi Warren, What is the value of the shunt resistor? 73, Stefan Am 09.04.2013 17:00, schrieb Warren Ziegler: Hi Stefan, I think you are advocating higher voltage and lower current to decrease loss in
Clemens, Thank you! Warren On Mon, Apr 8, 2013 at 3:42 PM, Clemens Paul <[email protected]> wrote: Hi Warren, I know a German OM (RF engineer) who has recently implemented a hall sensor for overcurrent
Ah interesting problem Warren.... why is it over-current?? if it is over-current because a high voltage has welded/melted a short between drain and source, then the protection wont help ....high cur
Ah yes that is Class D and can go that way if mis-matched......that is a lot of power in a sensing resistor! I guess a Hall effect device or even a temp sensor would do that job. I think in over curr
Hi Warren, Indeed it requires a few milliseconds (the small reed relay contacts can switch at one or two hundred Hertz) but you don't need to shut off the MOSFET within a few thousand cycles of the c
Hello Warren, that should be possible, I have used a A1302 Hall sensor as a "no contact" >100A current monitor. The sensor was just some mm away from the wire and was calibrated once using a (expe
Hi Wolf I cant remember the ratings now but breaking 18A+ might be a bit cruel :-)) It would probably need more than a tap with a pencil to unstick it ! Alan G3NYK -- Original Message -- From: dl4yhf
Hi Warren, I know a German OM (RF engineer) who has recently implemented a hall sensor for overcurrent shutdown for his home built 1KW short wave FET PA successfully. I will ask him if he is willing
.. or wind a few turns of fat copper wire around a 'reed relay' contact tube. Virtually no voltage loss then. I used this for a power supply, but it would work for the DC current feed inside a PA as
Hi Warren, Instead of spending to much effort to the current sensing my advice is to use other FETs. A 500 V FET at 30 V supply voltage is a heavy waste of power in the on resistance. For 30 V and a
Hi Alan, Of course when the reed switch closes, it must not (never, ever) directly switch the drain current ! (To do that, one would need an "opener" which are quite exotic devices for reed switches,
Wolf, interesting idea, but doesn't contact closure take about 10ms? 73 Warren On Mon, Apr 8, 2013 at 4:18 PM, wolf_dl4yhf <[email protected]> wrote: .. or wind a few turns of fat copper wire around
Hi Warren, Instead of spending to much effort to the current sensing my advice is to use other FETs. A 500 V FET at 30 V supply voltage is a heavy waste of power in the on resistance. For 30 V and a
Hi Warren, What is the value of the shunt resistor? 73, Stefan Am 09.04.2013 17:00, schrieb Warren Ziegler: Hi Stefan, I think you are advocating higher voltage and lower current to decrease lo
Ah interesting problem Warren.... why is it over-current?? if it is over-current because a high voltage has welded/melted a short between drain and source, then the protection wont help ....high curr
Hello Warren, that should be possible, I have used a A1302 Hall sensor as a "no contact" >100A current monitor. The sensor was just some mm away from the wire and was calibrated once using a (expensi
Hi Stefan that might be taking a bit of a risk! A 100v working FET might be ok at 24 V but the recommended minimum rating is 4 times the DC supply for Class D and E. It does mean you have to put up w
