Keeping Things Isolated

Why Use Isolated Power Supplies

With most hobby electronics, all your system parts tend to operate from a common ground.  This makes things easy to understand, as you just measure what a device is 'doing' with respect to ground, and you can make things happen in your design.

For example, you can decide that 5V above ground is logic high, and if your micro sees that level on a pin ou can turn on a light. Or if it's an analogue value of 3.2 volts you might think your room is warm enough and decide to turn off your heater.

Sometimes you might here this referred to as an 'absolute value' above ground.

Makes sense.

But sometimes, you don't want to know what the difference is between two points that are different to ground.

Huh?

Getting one up on the kids!

Free Stuff!

Over at the EEVBlog forum a PCB Fab house by the name of JAKO made an offer - FREE 5x5 cm PCB Service.

Woot!

iPhone 4 Screen Teardown

Reduce. Reuse. Recycle!

In an effort to get fit, I'd been going for long walks.  Anyway, I enjoy listening to podcasts while doing so, and I did this on my trusty iPhone 4.

Or should I say 'rusty'  The sweat in my pocket payed havoc with the end connector and when some obvious (non-photographed) corrosion set in I couldn't charge my phone.  Eeep.

So out with the contact cleaner and toothbrush and I could soon charge my phone again, but the contact cleaner seeped up into the phone and left cloudy dark spots on my screen, just like this. Again I'd taken no photos of my own at this stage.

But at the end I got some sweet LEDs to play with!

The Not So Obvious Telephone

Yep, after practising engineering for 18 odd years, I'm still (too) often dumbfounded about how simple things work. Like the telephone. Been around since 1876, and didn't require electronics as we know it to work - just batteries, wires and coils.