Inspired by #keysightlabs and #danielbogdanoff, latest YouTube video, where he uses a super nice #keysightoscilloscope to demonstrate reactive (negative) power, I decided to make my own setup and replicate his experiment.

I don’t have an advanced scope as the one he used, but I can create a voltage vs current phase difference by changing the frequency of a signal I pass through an RC circuit.

Measuring the current with a differential probe, lets me multiply current and voltage and display a power curve on the oscilloscope (sorry for the weird colors, my camera messed up).

As you can see, with a phase difference between voltage and current, I get negative power: the top curve begins to move below zero. At 90 degrees difference, the power would average zero which is why inductors and capacitors never really heat up (besides the resistive loss ofc) 🙂

#electronics #signalsaturday #siglent #micsig #engineer #electronicsengineering #testandmeasurement #hamr #hamradio

Inspired by a Twitter dialogue, let’s launch some daily #electronics tags to be used freely 👍🏼🤓

Today is #waveformwednesday and here’s how my mains grid looks - not quite a sine but that’s to be expected.

Don’t ever, EVER, connect your scope input directly to mains - use a high voltage differential probe or a transformer, as shown here.

I’m using the #quicktest switch, it’s a really handy way to control power to a circuit. It’s of British origin and comes with a standard 13A BS1362 fuse. I found that a bit high for my purposes, so I replaced it with a 5A, significantly limiting the available energy in case of a fault situation. Safety first always applies at the bench 👍🏼⚡️☝🏻

So go ahead, use these tags freely, be inspired and show us your experiments 👌🏻🙂

#electronics #rohdeschwarz #micsig #electronicsengineering #engineer #hamradio #measurementmonday #testgeartuesday #waveformwednesday #teardownthursday #frequencyfriday #signalsaturday #sensorsunday

Differential Probe Clocks at 100MHz and $200

[Voltlog] often looks at interesting test equipment and in the video below he reviews something that isn't very common in hobby labs: a differential oscilloscope probe. These are usually pretty expensive, but the Micsig probe in the video costs under $200. The question, of course, is what do you need with a differential probe?

A typical scope probe has a ground lead that connects directly to the actual grounding point. This can cause a problem if you try to measure across some component that has more voltage than you want to short to ground. It might hurt your device under test, your scope, or both.

The probe isn't isolated in the traditional sense, but it does prevent the problem, as he explains in the video. The probe powers from USB, which might seem odd, but [Voltlog] points out that you probably won't use this often, so batteries that will go bad during the months it sits on the shelf aren't really a great idea. Makes sense.

Towards the end, you can see the probe in action, measuring signals in a switching power supply that would be difficult to measure with a conventional probe. If you'd rather build your own probe, start with this entry to the Hackaday Prize. Or, try this older design.

#toolhacks #differentialprobe #micsig #scopeprobe