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May 19, 2012
Product PRT-00114 |
about 2 months ago
What’s the input voltage? If it’s more than, say, 12 volts, it’ll get pretty darn hot. However, you’re in luck because the LM317 has built in thermal overload protection, so that if the regulator gets hot as a result of using the wrong AC adapter, or a downstream component failing shorted, it will temporarily shut down (technically it drops the voltage-it doesn’t shut off completely-but it generally has the same effect)
Run the numbers based on your input voltage (Vin - Vout) * Amps = Watts. In a nutshell, the bigger the difference between Vin and Vout, the hotter the regulator will get under the same current draw. At some point this will be too much, but as mentioned above, the regulator has thermal overload protection (Don’t ask me how they put that in the TO220 case) so it’s not going to ruin it, at least not right away. However, a prolonged or repeated overheat condition could still shorten the life of the regulator-hence the need for a heat sink.
Product COM-10444 |
about 3 months ago
You might be able to drive a transistor or a mosfet with this. Your current requirement is relatively low, so a small signal transistor will probably work as long as you remain within the maximum watts dissipated on the transistor. I would recommend picking a transistor whose maximum wattage is 25% to 50% higher than the normal load of the circuit. The cost increase would be marginal for this type of thing, and it will probably last longer.
Product COM-11232 |
about a year ago
According to the datasheet, it will work down to 2.7 volts at 8mhz, which makes this chip ideal for battery powered projects, since battery voltage goes down as the batteries die. Yet, it will also work fine at 5 volts (mine is running off of that and it hasn’t left a crater in my breadboard) so it could run directly off of 3 AA batteries (1.5 v * 3 = 4.5 for alkalines, 1.2 * 3 = 3.6 for rechargeables)
Of course, you could use 6 AA batteries and a 5v regulator, but who wants to use that many batteries? I use rechargeable AA batteries to power my portable projects and a 9v 1000 mA, UL listed DC power supply for my stationary ones (with the appropriate regulators of course)
BTW, http://hlt.media.mit.edu/?p=1695 has a solution for those who want to make smaller projects using the Arduino environment. This makes for a relatively inexpensive project if you’re looking to make a few small “light show” type devices and/or you’re good at multiplexing. Since the Arduino Uno can be used as an ISP, I recommend picking up one of those, because you’ll get to work with a pre-made board off the bat and then “graduate” to using one to program another.
Product COM-11459 |
about a year ago
Do these have built in resistors? I don’t think the coin cell battery would work with them directly without ruining them otherwise. Unless 3 volts can light an LED directly without ruining it due to the voltage drop?
Product TOL-10240 |
about 2 years ago
A water soluble flux core is easier to clean off (because you just use water!) but it is bad news if you leave it on the circuit board after soldering. It can cause corrosion over time which is less than entirely desirable in most cases :) You don’t need to soak it (nor do I recommend that :) just use a paintbrush or Q tip wet with water and wipe off the solder joints.
Just wash your hands afterwards and you’ll be fine. I’ve handled LEAD BASED solder with my bare hands and I just washed my hands afterwards. Ain’t suffered no ill effects. You’d probably have to hold the solder in your mouth to be poisoned by anything that’s in it. That would probably be worse with lead solder, but who would put solder of any kind, or wires for that matter, into their mouth? Remember, lead based solder is usually something like 40% or 37% lead, but there’s only 0.15% antimony in this. Do the math.
No public wish lists :(