OK, my electronics expert readers, here is another brain-teaser for us to discuss and help this Australian gentleman who contacted me recently. I have not yet researched this product, but I think the design concepts and conditions might be interesting to examine.
Here is the email and details from our reader:
I chanced upon your website and wondered if anyone there could take a minute to ponder an electronic circuitry problem? I have several combination “Click” brand Night Light Motion Activated Flashlights* in my home (see photos). The problem is they have all failed from overheating after about a year, and I wondered if anyone there could tell me why. I'm not an electronics minded person though I have a basic understanding of components. The component that always fails (melts and disappears actually) is a 2.4k resistor.
Replacing with the same kind of resistor hasn't helped. I assume other components have failed, too, notably the polyester capacitor above it. Input is 240V AC 50Hz (Australian mains). Whilst the devices are only $20 to replace, it's a problem I'd like to solve.
*If you aren't familiar with the device, it's incredibly handy. It plugs into mains power and:
- Charges the flashlight
- Provides motion sensor illumination in the dark
- Illuminates when mains power fails
- Illuminates when flashlight removed from cradle.
If you have any insights I'd be most grateful.
Editor : Let’s dig into this issue and help our Australian reader with this problem and maybe come up with a fault condition and maybe a better design.