Latest threads in Hobby Electronics Basicsshow only best voted threads
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buying a UPS for my new PC
i am buying a new PC that is coming with a 600 watt power supply and I have an existing APC BACKUP that has 750VA and 450 Watts....... is this good enough for my new PC?
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11 years ago
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Simple Test for Coil On "Wasted Spark" 2 Cylinder Engine
I suspected a CDI coil wouldn't put out enough voltage for the "energy transfer" -- the worst misnomer ever -- system and suggested shorting out the spark plug electrode on one of the 2 cylinders by...
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11 years ago
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connecting wires to pencils underwater
I'm interested in the prospect of using pencils as electrodes for electrolysis of water, but I'm trying to figure out a way to attach the wires from the power supply to the other end of each pencil so...
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11 years ago
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LM339 Comparator input limits?
The LM339 spec sheet indicates the maximum negative input voltage should not be more than -0.3 volts. The schematic shows the input connected to the base of a PNP transistor with the collector at the...
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11 years ago
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Charging a marine battery
About 3 months ago, I purchased a deep cycle marine battery (12v) from Costco. It probably weighs 60 pounds. The application I intended for it is slowly proceeding, and I haven't used the battery at...
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11 years ago
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Driving a big LED with a MOSFET
I'm trying to drive a big LED (3W) with a MOSFET. Eventually I want to drive it with an Arduino but so far I'm failing to get the right numbers in my test circuit. My test circuit is like this: +5 |...
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11 years ago
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Charging an alarm battery
I have a Xantrex 12v rechargeable 600 Power Pack battery. Yesterday I charged it up and then attached a 12v smaller alarm battery. I forgot to check a few hours later. However, 8 hours later I...
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11 years ago
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*small* spark generator
I need to generate sparks between two pieces of brass, about a half inch apart or slightly more. I want each spark to be triggered by a logic line going high (going low would work, too.) The voltage...
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11 years ago
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Burnt out Electric Fence Tape
Hi guys, Anyone got any answers to an odd phenomena i've seen with an electric fence tape. The tape in 1/2 inch wide insulated with about 5 or six stainless strands woven through it. I have a 30ft...
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11 years ago
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Step Up Pre Coil/Transformer
OK Honda no longer makes the original ignition coil that steps up the voltage by 3 -4 orders of magnitude. What's the easiest way to get a 40,000 volt spark out of a 12 volt ac system with a 100X step...
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11 years ago
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Tesla generator
Has anyone actually made one of these out of four diodes and four capacitors. If so how much aerial is needed and what voltage was obtained? R
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11 years ago
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Curious about white LED circuit
I bought a few surplus pc boards that contain 29 LEDs and some resistors. 13" long x 2" wide. The wiring seems odd, there are two circuits repeated. The first: two series LEDs in series with a 560 ohm...
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11 years ago
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OT: Oooops!
Oooops! Technology has caught up with me... Looks like the modern world of home theater all talks HDMI. (All my present A/V is 18 years old :-) So I looking for receiver recommendations. I'm looking...
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11 years ago
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Where do I find this part?
Where do I find this part?.... It's a rubber cabinet foot, made in the style of automotive panel fasteners... insert into hole, push pin in to lock. My surfing comes up zilch. Maybe some of you...
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11 years ago
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Why Would Spark Ignition Need Rectification?
For an inline 4 with 2 coils, car or motorcycle there's no polarity switching diodes - usually the pickup coil flips a bistable to & fro to drive the LT circuit switching transistors. Its called the;...
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11 years ago
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