These little buggers can come in useful at times but, wherever possible, use a two-pronged pokey tester (GS38 compliant here in the UK.) I've had a few of these over the years. One of them didn't detect anything and I watched a cable go bang as I chopped through it. I had another two that you could lay next to a heap of dog shit and they'd light up! They work on capacitance as far as I remember.... they're not as bad as the screwdriver type testers though. If the resistor in the thing is buggered, you're going to rubbing your hand and swearing for a minute or so. Been there too! :D
Ok, first of all it’s not detecting current, which is electricity flowing. It’s detecting voltage, which is more like the potential for electricity to flow. The reason it was detecting voltage on the power strip is because it’s a poorly made power strip, and it’s still allowing some voltage onto the hot leg even though the switch is off. It’s not enough for devices that require 120V (or 110+ really) to actually turn on and function properly, but it’s not zero like it should be. Grab a decent little affordable multimeter like the Klein MM325, and you can actually test to see how much voltage is leaking before you toss that power strip out and get a new, better one :)
I could see that being handy and for other experimenting as well.
These little buggers can come in useful at times but, wherever possible, use a two-pronged pokey tester (GS38 compliant here in the UK.) I've had a few of these over the years. One of them didn't detect anything and I watched a cable go bang as I chopped through it. I had another two that you could lay next to a heap of dog shit and they'd light up! They work on capacitance as far as I remember.... they're not as bad as the screwdriver type testers though. If the resistor in the thing is buggered, you're going to rubbing your hand and swearing for a minute or so. Been there too! :D
Ok, first of all it’s not detecting current, which is electricity flowing. It’s detecting voltage, which is more like the potential for electricity to flow. The reason it was detecting voltage on the power strip is because it’s a poorly made power strip, and it’s still allowing some voltage onto the hot leg even though the switch is off. It’s not enough for devices that require 120V (or 110+ really) to actually turn on and function properly, but it’s not zero like it should be.
Grab a decent little affordable multimeter like the Klein MM325, and you can actually test to see how much voltage is leaking before you toss that power strip out and get a new, better one :)