Step Up Pre Coil/Transformer

Started by Bret Cahill in sci.electronics.basics8 years ago 3 replies

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...

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 up coil? Bret Cahill


Designing The Perfect Coil?

Started by Ron Hubbard in sci.electronics.basics8 years ago 113 replies

I want to do an experiment in brainwave entrainment by making a 7 Hz sine wave oscillator out of an XR2206 frequency generator IC and a LM386...

I want to do an experiment in brainwave entrainment by making a 7 Hz sine wave oscillator out of an XR2206 frequency generator IC and a LM386 amplifier feeding a six inch diameter coil-- which should probably fit around my fat head. ;-) The LM386 has an 8 ohm output, so it shouldn't be hard to find a speaker, if I wanted to use one; but I don't know how to make a good 8 ohm coil to radia...


Inductance calculations

Started by Peter Percival in sci.electronics.basics8 months ago 5 replies

Somewhere there must be a formula for the inductance of a hand-wound coil. Air core, one layer of wire (of given swg) close-wound, diameter of...

Somewhere there must be a formula for the inductance of a hand-wound coil. Air core, one layer of wire (of given swg) close-wound, diameter of former (cardboard, probably inside of toilet paper roll), length of coil,... (what else?), therefore inductance equals ...


Simple Test for Coil On "Wasted Spark" 2 Cylinder Engine

Started by Bret Cahill in sci.electronics.basics2 years ago 26 replies

I suspected a CDI coil wouldn't put out enough voltage for the "energy transfer" -- the worst misnomer ever -- system and suggested shorting out...

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 pounding the gap shut or stuffing it with a bit of foil. The theory was instead of jumping two gaps it would only need to jump one. The lower effective resistance would give a better spark on t...


6#11oz, 20"

Started by Jim Thompson in sci.electronics.basics6 years ago 7 replies

6#11oz, 20", our first great-granddaughter... Olivia Lawless... Father: Chris Lawless Mother: Caitlin Coil Lawless, first daughter of our...

6#11oz, 20", our first great-granddaughter... Olivia Lawless... Father: Chris Lawless Mother: Caitlin Coil Lawless, first daughter of our oldest daughter Madeleine and James Coil (Yuma County Judge). ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | ...


Automotive relay question

Started by DaveC in sci.electronics.basics5 years ago 15 replies

I have a 12V SPST cube relay in my junque box. The diagram molded into the relay?s housing includes a component connected in parallel with the...

I have a 12V SPST cube relay in my junque box. The diagram molded into the relay?s housing includes a component connected in parallel with the coil which looks suspiciously like a resistor. It?s not a back-emf diode: I connected the relay coil using both polarities (using a current-limited power supply) and the same current draw is measured. What is the purpose of this resistor? ...


Automotive relay question

Started by DaveC in sci.electronics.basics5 years ago 2 replies

I have a 12V SPST cube relay in my junque box. The diagram molded into the relay?s housing includes a component connected in parallel with the...

I have a 12V SPST cube relay in my junque box. The diagram molded into the relay?s housing includes a component connected in parallel with the coil which looks suspiciously like a resistor. It?s not a back-emf diode: I connected the relay coil using both polarities (using a current-limited power supply) and the same current draw is measured. What is the purpose of this resistor? ...


MOSFET switching an inductive, high-frequency load

Started by Don Gilmore in sci.electronics.basics6 years ago 8 replies

Guys: I'm an ME working on a project where I must switch voltage to a small coil = on and off at a fairly high frequency (around 25 kHz) with...

Guys: I'm an ME working on a project where I must switch voltage to a small coil = on and off at a fairly high frequency (around 25 kHz) with a MOSFET transis= tor. The DC resistance of the coil is very low (about 1 ohm), but the impe= dance is much higher because of the frequency (about 100 ohms). I'm switch= ing 24 Vdc. Should I specify the max. pulsed current of the transistor based...


Creating sparks with a mosfet and ignition coil

Started by Anonymous in sci.electronics.basics6 years ago 29 replies

I would like to generate a series of ~1000 volt sparks continuously, for several hours, using a spare automotive ignition coil I have lying...

I would like to generate a series of ~1000 volt sparks continuously, for several hours, using a spare automotive ignition coil I have lying around. I found this 555 circuit online: http://www.sci-experiments.com/HighVoltagePulser/ My questions: (1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright without frying? (2) Does the 0.1 uF, 250V capacitor take the ...


How Do They Get So Much Money for Grid Ties?

Started by Bret Cahill in sci.electronics.basics7 years ago 2 replies

Are there still some unexpired patents out there? Does a grid tie require a 200 lb copper coil? Bret Cahill

Are there still some unexpired patents out there? Does a grid tie require a 200 lb copper coil? Bret Cahill


Bifilar inductor?

Started by George Herold in sci.electronics.basics2 years ago 27 replies

Hi all, silly question. Dave's EEVblog was on... there was this bifilar wound coil (starts at ~39 minutes in) https://www.eevblog.com/ (hmm...

Hi all, silly question. Dave's EEVblog was on... there was this bifilar wound coil (starts at ~39 minutes in) https://www.eevblog.com/ (hmm latest video I guess, Mailbag #1049) My question is; how the heck does that do anything inductive? George H.


Coils

Started by Chiron in sci.electronics.basics8 years ago 35 replies

I've wanted to check out some things using big coils - not the sort used for RF circuits, but large coils such as might be found in a Tesla...

I've wanted to check out some things using big coils - not the sort used for RF circuits, but large coils such as might be found in a Tesla coil. I don't have the funds to special order them or to buy them pre-made (assuming they even come that way). I expect I'll have to wind my own... but... How the heck do you do that? What sort of arrangement would work for that? Trying it by ...


Hey, that's wierd.

Started by Uncle Steve in sci.electronics.basics7 years ago 18 replies

I'm seeing something really interesting with the coil I built. I wired up a buck converter circuit yesterday and tried it out, but just with a...

I'm seeing something really interesting with the coil I built. I wired up a buck converter circuit yesterday and tried it out, but just with a switch and resistor tied to the gate of an IRF-1404PbF, which lists a Total Gate Charge of 131nC, which I take to mean nano- coulombs. When the circuit is 'rested', power applied does what is expected. 10uH ...


What does this circuit do?

Started by Stumpy in sci.electronics.basics5 years ago 21 replies

If anything. http://reliablehomeenergy.net/wp-content/uploads/2015/03/scheme.png They claim that $49 for instructions, $63 for parts get you...

If anything. http://reliablehomeenergy.net/wp-content/uploads/2015/03/scheme.png They claim that $49 for instructions, $63 for parts get you a single home "magnetic energy generator" designed by Tesla. http://reliablehomeenergy.net/tl I assume the video has an AC coil under the table.


Wa-a-ay OT: Overlay to make a cable "coiled"

Started by Jim Thompson in sci.electronics.basics7 years ago 13 replies

Back when I was a kid (nearly 3/4 of a century ago :-) there used to be plastic coils that could be applied to a straight cable to "coil" it...

Back when I was a kid (nearly 3/4 of a century ago :-) there used to be plastic coils that could be applied to a straight cable to "coil" it up. Does such a thing exist today? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-S...


How to bootstrap

Started by amdx in sci.electronics.basics7 years ago 37 replies

I see the term bootstrapping, used when the designer wants a high impedance and usually low capacitance. I know it involves feedback but that's...

I see the term bootstrapping, used when the designer wants a high impedance and usually low capacitance. I know it involves feedback but that's all I know. I want to learn enough to build a bootstrapped input with 10Meg/2pf impedance. Those are ballpark numbers, the end use would be used to measure voltage on a high Q coil and NOT load it. Frequency 100khz up to 2Mhz, but 10 Mhz adds mor...


Inductance Equations using SI Units

Started by chiron613 in sci.electronics.basics8 years ago 15 replies

I've been planning to wind some coils. I want to get an idea of what sort of inductance I'd get for a given winding, coil diameter and length,...

I've been planning to wind some coils. I want to get an idea of what sort of inductance I'd get for a given winding, coil diameter and length, and so on. These are all air-core, so I don't need to take into account the effects of iron. When I Google for information, I seem to get the same few formulas, none of which are in SI units. I can find equations and formulas that use inches, or ...


Wireless phone charger

Started by Steve Wolf in sci.electronics.basics1 month ago 5 replies

Just for fun I thought I would make a wireless phone charger. I'm not reall= y going to use it but I wanted to build it and just see if it...

Just for fun I thought I would make a wireless phone charger. I'm not reall= y going to use it but I wanted to build it and just see if it actually work= ed. The circuit uses two coils and a 2n222 transistor very simple. Well I can't really get it to work maybe I could get half a volt maybe to p= ast through induction. Then it seems to stop. I connected my meter to the r= eceiving coil to t...


Difference in Coils for Electronic Ignition & Mechanical Ignition

Started by Bret Cahill in sci.electronics.basics8 years ago 6 replies

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


The wiper in a variac

Started by Robert Roland in sci.electronics.basics2 years ago 7 replies

I have been thinking about the way a variac works. One thing that puzzles me, is the wiper design: If the wiper is too narrow, the output...

I have been thinking about the way a variac works. One thing that puzzles me, is the wiper design: If the wiper is too narrow, the output voltage will cut out when the wiper is between two turns of the coil. If the wiper is too wide, it will bridge two contact points, causing one turn of the transformer to be directly shorted. Although it is not a lot of voltage, it is also not a long pi...