These torches became very popular in south Africa a couple of years ago when we were plagued with blackouts.
It consist of a coil of copper wire with a magnet in the centre that slides through the copper coil when shaken. This action creates an electrical current in the coil, which in turn charges a rechargeable battery (or super capacitor).
This action is known as Faraday’s induction, something that we learned in high school.
These torches are very impressive when you buy them – one hardly needs to shake them and they give a decent light from the LED.
Unfortunately the fun ends as soon as the internal battery gets flat. You then need to permanently shake the torch to get the LED light to shine bright. The problem is shaking the torch only generates a very small current to charge the battery – you will get roughly 10 seconds of light from 10 seconds of shaking – quite hard on the elbows!
I’ve even seen some of these torches that didn’t have a rechargeable battery – they use a small lithium battery that last quite long, but after that it’s impossible to store the charge.
My conclusion: I’m afraid this is only a cool gadget – fun to play with, but not really useful.
Who would not want to improve the reception on their cellphone, especially if you only need to stick an antenna on the battery and voila!
I was lucky enough to receive $19.99 “As seen on TV” Cell Antenna for free when I bought my car radio. What a bargain – it’s like having a four foot antenna on your phone, reduces static, improves signal strength, and it works on any phone!
All you have to do is open your phone and stick this magical antenna onto the battery.
As you can probably guess by now, this is a total scam. For it to even have the remotest of changes to work, it should at least be made of a conducting material, like copper (which it looks like.) But when testing it for conductivity with a multimeter, it didn’t conduct at all.
This is just what it looks like – a shiny sticker – nothing more!
Nowadays supermarket shelves are loaded with dubious gadgets. Some claim to improve cellphone reception or block harmful radiation, others repel insects with sound waves or improve fuel consumption with magnetic fields.
Some of them work, some errr… not quite.
Problem with most of these gadgets is that its very difficult to know if they work without extensive testing. We’ve decided to try a few and hopefully stop you from making a silly purchase.