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...

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 supply is 6v or 12v from a battery. The problem is that I need the circuit to fit inside a 1.5" inside diameter PVC pipe, and not take up more than, say, 3" of the pipe length, discounting battery...

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 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 negative supply terminal. So, it looks like if the input or base of the transistor goes more negative than about 0.7 volts relative to the negative supply point, the transistor will conduct like ...

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...

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 | [R1] (8 Ohms) | D G -[R2]--- JUMPER S | LED | GND I can connect the jumper cable to +5V or ground and it switches on/off as expected. My MOSFET is one of th...

I have an IR remote that needs cleaning since the buttons require excessive force to operate. I tried alcohol and a toothbrush on the circuit...

I have an IR remote that needs cleaning since the buttons require excessive force to operate. I tried alcohol and a toothbrush on the circuit board where the buttons make contact, but it didn't last long, and I had to do it again. The second time, I soaked the rubber keypad in soapy water for a couple days and cleaned it with a toothbrush and also recleaned the board with alcohol. Seems OK at...

Maybe the voltages vary somewhat for different point and plug gaps but is it enough to make any difference? . Supposedly Honda no longer...

Maybe the voltages vary somewhat for different point and plug gaps but is it enough to make any difference? . Supposedly Honda no longer makes the coils for their 100 outboard, a 2 cylinder 4 stroke engine. Isn't it likely that other small engines, say from riding lawnmowers, use coils that are pretty much the same? For that matter couldn't a motor vehicle coil work? Bret Cahill ...

I have a 1 GHz 1/4 W whip driving a detector that outputs RF level data as a D.C. reading that is easily convertible to dBm. However I need the...

I have a 1 GHz 1/4 W whip driving a detector that outputs RF level data as a D.C. reading that is easily convertible to dBm. However I need the reading presented in mW / cm^2 I understand that my antenna has a gain of 1 dBi. In this chart http://www.geopathfinder.com/Conversion Chart.pdf ..I see that 0 dBm (for example) is equal to 0.0121 mW / cm^2 The chart refers to an equation sou...

A wiki article said some of the mechanical distributors could simply be swapped out with electronic ignition distributors. They didn't say if...

A wiki article said some of the mechanical distributors could simply be swapped out with electronic ignition distributors. They didn't say if a new coil was necessary. Bret Cahill

This time I built two astable circuits, using different designs (from the same book), on the two timers in one TI NE556 chip. Timer A: ...

This time I built two astable circuits, using different designs (from the same book), on the two timers in one TI NE556 chip. Timer A: reset pin --- Vcc discharge pin --- not connected control pin --- not connected output --/\/\-- trigger & threshold --|(-- ground Timer B: reset pin --- Vcc Vcc --/\/\-- discharge --/\/\--- trigger & threshold --|(- ground ...

I have a basic question about transformer ratios, if I have 3 windings, a pri, a sec and an aux, what's the voltage expression for each winding?...

I have a basic question about transformer ratios, if I have 3 windings, a pri, a sec and an aux, what's the voltage expression for each winding? My guess is Vpri = Npri/Nsec Vsec = Nsec/Npri Vaux = Naux/Npri is this right? thanx!

So I'm playing with a AVR PiC, the ATMEGA32. And its needs 16mhz crystal hooked to it like so: http://tinypic.com/r/ei9im9/5 Note; I used a...

So I'm playing with a AVR PiC, the ATMEGA32. And its needs 16mhz crystal hooked to it like so: http://tinypic.com/r/ei9im9/5 Note; I used a Cap and Inductor pair for the crystal symbol. I am just wondering what is the role of the capacitors? Can I use 1uf caps instead and still get 16Mhz?