In aluminum heat sinks for controllers and drivers I often thread form 6-32.
In aluminum heat sinks for controllers and drivers I often thread form 6-32.
They still sell erector sets, they are quite plentiful.
i
That's cool. I use a reversing switch on the output of these regulators, so not as easy to have a soft start. Maybe one day I will so something like that.
i
We used a variable power supply quite a bit to arrive at an acceptable voltage. Overall, 5v was perfect, anything faster was just too hard to control.
i
Any suggestions?
This is cool, indeed!
i
It'd be better if you used no tapping at all, just a smaller bolt (#4-40). The force needed to get a #6-32 into an undersize hole can warp the surface (and hurt the heatsinking). It can also make it hard to stop when the torque is 'enough': the copper of the heatsink tab can be deformed, and that makes for a TERRIBLE thermal connection.
"Ignoramus32423" wrote in message news:htqdnX6N4ZDDcb snipped-for-privacy@giganews.com...
The problem with them is the low maximum voltage rating of 7V. I have a similar AboveTEK meter.
This has a more useful 33V rating and resolves to 0.1mA below 1A, 1mA above.
It also shows total power like a KillAWatt for DC. I haven't tried the simpler, less expensive versions.
-jsw
So it is. Thanks for the correction. The difference between 6-32 & 8-32 remains as stated, though.
Hul
BQ340 wrote:
It could waste less heat if the voltage is set a bit higher than with you existing regulators. Or it could waste more if the setting is lower.
But you can use switching regulators. And you could probably use something like a Arduino to sense the voltage and control a transistor . In short a switching regulator with intelligence so you could have that soft start.
Dan
The cheap ones are far from accurate. I bought 2 on ebay - both were in-accurate, and they didn't even match each other. (readings were different and didn't match my 3 multitesters, that all agreed within less than 1/10 volt and less than 1/100 amp
I've always considered 32tpi to be "fine", too. I guess there are
6-40 and 8-40 threads for the fine side, though I don't recall ever seeing one so far in this lifetime.
Look closely, mine had tiny calibration trim pots.
Most kids are stuck with Legos, the NON-hardware building set. Sad. They aren't learning about how to keep from getting cut by sheetmetal, how to use nuts or bolts or wrenches or hand tools, or anything metal stiffness/strength-related.
I guess they still make Lincoln Logs (no gay references, please) for kids, too, but CRIKEY, look at the price!)
I checked the charging current from the computer vs. the wall wart charger for my Kindle and the computer was 1/3 the current, taking a whole lot longer. It surprised me, but now I use the wall charger exclusively, unless I'll be at the computer all day.
I bought one of those solar wattmeters o eBay for $14 or so and it works well for 12v. The little ones above are USB, so they are for 5v USB circuits only. Since Ig said 5v, I keyed on it.
I forgot to check the charging rate of the little USB wattmeter through the solar charge controller, but will do that tomorrow. (Where the 'ell did I hide the little bastid, anyway?)
These useless pieces of scrap didn't.
How much was a motorized 650 peice set back in 1965 dollars?? I remeber they were too expensive for my family to buy for me. A mechanic made about $2.15 an hour, an electrician about $2.50 Today the earningas are at least 20 times that, so a $175 set today would cost the same at $8.75 in 1965. I'm sure they were more than $8.75 - A #11 kit was well over $25 (over 17 pd Stirling in the UK) in
1964(These were NEVER an "inexpensive" toy!!!)
[ ... ]
Hmm ... if using the variable regulators, put a limiting resistor in series with the control voltage, and an electrolytic capacitor to slow the ramp-up. (Put a diode in parallel with the resistor to make the ramp-down faster, however, to make it easier to stop before a crash. :-)
Enjoy, DoN.
I turned the cable and a connector from a USB1 hub into a breakout cable to check the AboveTEK meter with a DVM and an external resistor load.
AFAIK USB2 ports can supply 500mA continuously, for USB3 it's 900mA. They are protected (?) by PTC thermistors that allow higher startup surges. I'm not about to risk my laptops or portable hard drives by measuring these limits.
I run into them with a USB3 ExpressCard that won't run a portable hard drive without externally supplied 5V.
-jsw
They look like flathead mounting screws rather than pots. This one is
2mm in diameter.-jsw
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