Got this in from Bob:
“Hy Al, I have found a neat little circuit to lite LEDs. I use a dual LED with both Red and Grn and common anode (+).
What I needed was a way to switch from red to grn without having to have a relay as I only had a single switch SPST available. I connect the anode to a 2k resistor to +12 Vdc, and one ot the LEDs to Grd. Then I connect a 1.5K resistor to the other LED to a switch to -12 Vdc. When the switch is thrown the negative LED lights and the positive LED is backward biased. When the switch is open the positive LED lights. The resistors may be decreased for more light output.
My switch is an over the center crank that hits a pin to make the connection. This is very low cost switch machine for a lot of switches.
And Bob’s tip got me thinking – there’s been a number of posts on them over the years.
In fact, the list is endless. There’s years and years of posts now…
Hope you’ve found them helpful!
That’s all this time folks, it’s all becoming a little thin on the ground so please do mail me if you have anything you’d like to share.
If you want to search through the archives by the way, you can if you’re a Beginner’s Guide member.
PS Latest ebay cheat sheet is here. Some cracking deals about at the mo.