## classroom Van der graaff generator

Started by in sci.electronics.basics4 years ago 18 replies

https://pl.wikipedia.org/wiki/Plik:Van_de_graaf_generator.svg There are the positive charge on the sphere. But in the another description we...

https://pl.wikipedia.org/wiki/Plik:Van_de_graaf_generator.svg There are the positive charge on the sphere. But in the another description we can read: ""Although they look simple at first glance, the belt, combs, and rollers invisibly combine to form an electrostatic device called a Continuously Operating Electrophorus". From: http://amasci.com/emotor/belt.html "On average, the nega...

## Simulating Power Bandwidth

Started by in sci.electronics.basics6 years ago 24 replies

I'm trying to do a simulation to show power bandwidth for a (high power) OpAmp versus compensation capacitor. In the lab I would simply crank...

I'm trying to do a simulation to show power bandwidth for a (high power) OpAmp versus compensation capacitor. In the lab I would simply crank up the signal generator amplitude until the output became triangular rather than sinusoidal. Collect all the data for peak amplitudes versus frequency and then plot. Any ideas how I might do that automatically in a simulator, generating a family...

## *small* spark generator

Started by in sci.electronics.basics8 years ago 20 replies

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...

## Designing The Perfect Coil?

Started by 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...

## Cheap display has weird frequency count

Started by in sci.electronics.basics3 years ago 2 replies

I bought an inexpensive volt/frequency led display from eBay. On a generator, I get the proper frequency display, around 60 Hz. When I tried it...

I bought an inexpensive volt/frequency led display from eBay. On a generator, I get the proper frequency display, around 60 Hz. When I tried it on a dc to ac inverter, square wave output, I get around 120 Hz. It's a two wire device, with power and signal coming off the same wire. What could I expect to see if a scope was connected to that inverter? The thing runs everything I've plugged int...

## Thermopile power supply in water heater control

Started by in sci.electronics.basics3 years ago 12 replies

I recently bought a gas water heater and made a point of getting one that didn't require external electrical power to operate. To my...

I recently bought a gas water heater and made a point of getting one that didn't require external electrical power to operate. To my astonishment, it nonetheless came with what behaves like a digital controller, complete with a green LED status light that must require close to 3 volts to turn on. The electronics are operated from a standard Honeywell thermopile generator producing 750 ...

## Need an Isolation Transformer?

Started by in sci.electronics.basics7 years ago 7 replies

I needed isolation from the line today, it reminded me of something I learned while building a Cockcroft-Walton high voltage generator. Use...

I needed isolation from the line today, it reminded me of something I learned while building a Cockcroft-Walton high voltage generator. Use two transformers back to back. Example, you have two 120V to 12V transformers, (120v in 12 out) connected to (12v in and you have 120V out). Or any two transformers with the same secondary voltage. Current limit depends on the transformer size. It wo...

## Combined CNC Plasma Cutting Machine for sale

Started by in sci.electronics.basics7 years ago

Combined CNC Plasma Cutting Machine for Sale at Ajan CNC. Specification: Ability to cut pipes ranged between 50 and 600mm diameter. Steel...

Combined CNC Plasma Cutting Machine for Sale at Ajan CNC. Specification: Ability to cut pipes ranged between 50 and 600mm diameter. Steel constructed body. Precision Plasma 130 / 260 Amper Generator. Automatic Torch Height Control. For more derails please visit http://ajancnc.com/en-us/index.php