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Re: Sbitx manual

 

Although those Nanos are no-name clones, the key component on them is normally a real Atmel microcontroller. I gather that some clones of the Atmel chip have started to appear; those should be avoided. Every?Nano clone I have bought has an actual Atmel chip. The Arduino designs are open source hardware, and the bootloader is open source software, so clones are completely legal.

The Nano clones use an inexpensive USB to serial chip from China (originally a CH340G; they have now shifted to a CH340C, which is even cheaper because it has a stable onboard frequency reference and does not require a crystal) rather than the FTDI chip used on a real Nano, but that does not affect their operation in ham applications. (You may have to do the extra step of installing a driver on Windows systems the?first time you connect one.) The FTDI chips are stupidly expensive; the Arduino Uno uses a second Atmel microcontroller just for USB-serial conversion because it's cheaper than the dedicated FTDI chip!

On Mon, Sep 5, 2022 at 4:26 PM Jerry Gaffke via <jgaffke=[email protected]> wrote:
Tayda looks like a good steer for a cheap PFET.
But be aware that the on resistance of an IRF5305 is 60 milli-Ohms, which is 20 times more than the part Gordon was working with.
So if your rig draws 10 Amps there will be a 10*0.060=0.6 volt drop across this PFET, and you may as well just use a big Schottky diode in series.

Also, IR/Infineon consider this part to be obsolete, so now only made by no-name second tier clone manufacturers.
For example, these guys list the manufacturer as "various".

Not necessarily a bad thing, there are thousands of uBitx's out there with a clone no-name Nano,
and the Nano is far more complicated than a PFET.

I've bought a bunch of stuff from Tayda at their alarmingly low prices, it all seems to work just fine.

Jerry, KE7ER


On Mon, Sep 5, 2022 at 11:41 AM, JerryP wrote:
If you're looking for a P-Channel MOSFET for a power switch then this may be able to use a IRF5305 - TO-220, 55V, 31A, 0.06Ohm RDS On @$0.78 each:
Tayda has a $5.00 minimum order and their USPS shipment is 8-16 days and low cost.? While they may not have everything, it's very low priced and good quality.
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