Calling All EE Students - Build a Simple Flyback Converter to Win an Oscilloscope, DC Power Supply, Hot Air Soldering Station, and More!

The prizes are a brilliant combination of test tools. The portable oscilloscope, plus the Electronic load, and the 1kW hot-air tool look great!! They would provide usefulness for many years during engineering careers. The RISC-V board looks interesting too.

This design challenge looks super-useful for those wanting to experiment or apply some theory and see what happens in practice.

If any students or other entrants need some advice during the challenge, for example if they get stuck, I'd be (and I'm sure others would be) happy to help remotely using the forum. Problems can be easily resolved by the collective knowledge of people on the forum.

I hope there are some high-voltage experiments! The photo belows shows how straightforward a flyback converter can be (with just a 555 and BJT and no feedback in this example). The photo is self-explanatory but I can sketch a circuit if anyone needs it. It is lighting up a small neon bulb. It also provides a slight electric shock if touched, due to the high voltage!

What is the voltage?

Good question : ) but I have no idea!

I'm too scared to apply an expensive multimeter, and the cheaper ones are not RMS-responding at the frequency.

However, I have this cool thing in the photo below that would be nice to turn into a high-voltage voltmeter one day!

It's a load of 100 Mohm resistors, all chained to make 1 Gohm sections from connector to connector, and rated at 2kV per section. 

Its going to be around 60V under that neon load (I think that's the voltage at which the gas ionizes), but open circuit could be a lot higher (but extremely low current capability).

Good question : ) but I have no idea!

I'm too scared to apply an expensive multimeter, and the cheaper ones are not RMS-responding at the frequency.

However, I have this cool thing in the photo below that would be nice to turn into a high-voltage voltmeter one day!

It's a load of 100 Mohm resistors, all chained to make 1 Gohm sections from connector to connector, and rated at 2kV per section. 

Its going to be around 60V under that neon load (I think that's the voltage at which the gas ionizes), but open circuit could be a lot higher (but extremely low current capability).

Is something like this needed? Is it possible to test it by voltage divider consisting 2 THT resistors (for example, set to divide 20x) in parallel with LED neon lamp?

I replaced the mistake LED. It is not LED of course

The output might just be a few hundred volts, it's unlikely to be much higher, but I think I'd still need some sort of FET buffer (since the current capability is going to be extremely low from that transformer) . I was thinking for that effort, I may as well make it capable of a few kV with the resistor chain (I didn't design this, it was given to me, so I would like to use it sometime, and a voltmeter project might be ideal for it). 

"I'm too scared to apply an expensive multimeter, ..."

/products/arduino/b/blog/posts/uno-blue-man-and-the-neon-light

When I did something similar with a simple boost converter, I used my Tek 'scope to look at the waveforms. I did take the precaution of putting a high-voltage avalanche diode (100V power MOSFET) across the neon to catch the voltage at about 120V. The MOSFET also introduced enough capacitance that it slowed the rise time enough that the voltage was only getting to 10-20V above the 120V clamp before the avalanche started running current, so it was all fairly safe whether or not the neon was striking (well within what the probes/oscilloscope are good for).

Hi Jon, That was great to read! I missed seeing that blog post before. Lots of interesting ideas there!

Also, neon lamps are great, they should be used more : )