Frequently Asked Questions
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February 3, 2010
about 2 years ago
The very first thing you want to do after getting this one is to connect the metal plate electrically with the black post (assuming that’s the one you’ll be using as the ground connection). The metal base serves as an excellent antenna for picking up the mains frequency from the air and radiating it back to whatever you’re breadbording. And that’s usually the last thing you want. I’ve wondered for some time why the signal from my opamp-based low signal microphone amplifier was swinging up and down until I realized that. Just connect the black post with one of the small Philips screws underneath or otherwise undo the electrical insulation between the GND post and the plate (by scraping the paint or whatever) and instead of spewing the interference on your circuit, the metal plate will serve as a great shielding from now on.
about 2 years ago
Ugh, so apparently there’s just no limit on how bad these could get. This makes me sad.
Don’t bother - the quality is terrible. They’re to loose and once you try to correct it, the “spring” contacts which are cut from extremely thin sheet metal wrapped around the solid metal prong get hopelessly bent out of shape and they lack any “springiness” whatsoever. There is some restriction designed in against “squashing” the contact spring part by not allowing it to expand in its length but they blew it by leaving some 1 mm gap in there. Not only are these plugs loose in the sockets, the thin sheet metal contacts also have their fair amount of play on the prong itself so the overall current carrying capacity goes down the drain. And the cables themselves are very stiff. It’s mind boggling how they managed to find so many ways to get such a ridiculously simple thing wrong. The very last thing you want from your banana cable is having to wiggle it for 5 minutes, arcing galore, before managing to get a “good” connection and then to not look at it funny in the fear of the connection going bad. Or maybe asking someone to apply a constant amount of pressure in the just right direction with their finger. You could probably get these from “leading auction service” for a dollar a dozen with free shipping but I’d still advise against. Good thing I only wasted $9.90 on these and “Banana to IC hook” instead of getting one of each combinations offered here.
Oh, did I mention just how hopeless they are?
about 4 years ago
It seems when you move a product to the “Retired” category, it’s making its way into the “New products” Atom feed which is rather pointless. Worth fixing, I guess.
about 4 years ago
And you didn’t find this information important enough to put ANYWHERE in the description? Come on guys, wake up, you ship your stuff internationally! I know it’s obvious to YOU that you are a U.S. company, but for the potential buyer - not necessarily so. You just have to realize that.
about 4 years ago
DC SSR is essentially just a MOSFET… Google ‘MOSFET as a switch’.
It’s worth noting it’s 400V peak, not RMS. If you’re living in the 230V part of the world, you should definitely go for a 600V version (S208T02, S202S02F). 400V peak is only ~280V RMS which leaves a quite low safety margin for continuous usage under 230V. By the way, these are listed as obsolete by Digi-Key - they list the S202S02F instead. Just saying.
To the guys looking for a way to make a light dimmer: you won’t make a proper dimmer by just getting a non-zero-crossing version of this one here - you’ll have to drive it with a zero-crossing sensing circuit. Google the U2008 IC instead. It’s a cool phase-control IC. It’s not as “plug-and-play” as this one here as it requires some external circuitry like the optocoupler on the input and an external power triac to trigger (it doesn’t carry the current by itself). But with proper few external elements you can control your mains load with a PWM output - how cool is that! Maybe there is some completely integrated solution like this one here. Somewhere. But I’m not aware of that.
A a footnote, Sparkfun should pay a little more attention to the customers from 230V parts of the world. You ship globally and have customers all around the world (me included) so the information on the mains voltage should scream at you in bold red font in the relevant product descriptions. Not like in case of soldering stations you carry, where the voltage info is just barely mentioned somewhere within the description. These days, when surfing for stuff, sometimes you don’t even bother to check where in the world the seller is located and OTOH you sometimes tend to take the “right” voltage for granted so it’s really important for you to pay a little more attention to that.
Tutorial - How To Use A Multimeter
about 4 years ago
I personally don’t like auto-off feature that much at all. Throughout the years I often had a need to observe some parameter over some longer period of time. Like keeping an eye on the charging/discharging process of a rechargeable battery. More than once I was so fed up with a meter switching itself off after few minutes while I was actually staring at it, I was close to go and buy a different model without auto-off just because of that. Batteries are cheap these days and IMO, you’d have to keep forgetting to turn it off all the time for the auto-off feature to be justified. The models with an auto-off feature with the “off” setting as a one of the positions of the selector wheel (without a dedicated on/off switch) are the worst combination possible. You have to switch them either to the adjacent position (with possible damaging effect when in powered circuit!) or all the way to the off and back. I guarantee you’ll want to throw such a meter out of the window while trying to sit there and catch the moment your LiPo discharges down to it’s critical voltage or so. The one I have now isn’t that bad as it warns you with a beep a minute before going to sleep and it’s enough to press a button to wake it up.
If you don’t have any DMM yet and want to buy one, buy two instead ;-) Or get one fancier one and one cheaper. Or two with similar appearance but slightly different features. No, seriously. These are so cheap these days there’s no reason not to. What’s the point? Simultaneous measurement of both voltage and current. Like testing how your power supply copes with increasing load in terms of the voltage drop. I can’t count how many times I was jumping through the hoops with my large and moderately fancy meter just trying to find out how the voltage output of my power supply drops with varying load and wanting to know what that load is at the same time. That’s nothing sophisticated at all - you’re more than likely needing to do this sooner or later if you’re seriously into this hobby. Now I got myself two not-so-fancy but small and cheap multimeters from the same product line but slightly different (last letter) models with more or less complementary feature sets (one of them is autoranging). But I’m sure two pieces of this one here will be just fine as well! You just have to prepare or buy a proper amount of the crocodile or breadboard-friendly cables as in the setup described you start to notice a serious shortage of hands are more likely to make some nasty mistakes. As a side note, there are at least two basic methods of simultaneous current and voltage measurement and none of them is “just right” in all the situations but well, that’s a whole another story…
about 4 years ago
- Don’t leave the CTRL0 and CTRL1 floating or it’ll freak out. Both should be grounded for testing with the default settings.
- As already mentioned before, “OUT2” on the board is really an OUT0 (the one without a divider; you probably want to use the OUT1).
- Be careful about the high frequency interference/crosstalks in long lines. I’ve wired mine via I2C to the Bus Pirate with the output additionally wired to BP’s AUX connector to be able to verify the actual frequencies while I was playing with it. It took me half a night to figure out why “suddenly” the I2C module freaked out and stopped responding to any communication attempt. Turned out the high frequency TTL-level signal in the ~15cm long ribbon cable totally jammed the I2C transmission. It was enough to crank up the frequency to anything north of 1MHz to completely FUBAR any I2C communication attempt in my case.
about 5 years ago
“will track up to 66 satellites at a time"
Yeah - good luck with that given there are only 30-something GPS satellites total on the orbits ;)
No public wish lists :(
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