4 of 4 people found this helpful
One neat use of switches is as limit switches on motor movement. When some mechanism reaches its mechanical limit, the switch gets pushed and cuts power to the motor so neither the motor nor the mechanism gets damaged by going too far or stalling. With a couple of diodes, a double pole limit switch can be set up so the motor can reverse away from the limit but cannot go forward past the limit. Microswitches with rollers are often used for this purpose - the roller lets the mechanism move past the trigger point a bit as the motor comes to a stop.
6 of 6 people found this helpful
Why not do the old double switch control where you can turn a light on with one switch and still turn it off from the other.
That example allows you to demonstrate a simple logic or gate plus a simple state machine example.
That's not a bad idea. A lot of homes have 3-way switches and it's useful to understand how and why they work. Thanks!
5 of 5 people found this helpful
I always thought this was fun (from a Radio Shack project book):
It uses a relay, but the normally closed contacts, to make a kind of oscillator, an almost similar thing was popular in tube radios in vehicles - jw0752 wrote a blog about it:
Anyway, it generates a high voltage! Touching the probes gives you a mini electric shock : )
Just to use it on Grandpa and blow out his pace maker.
A long time ago on an early TLC episode, I did an overview of switches. Sadly, the episode ran too long and we cut everything about poles and throws. I figured it was time to revisit that topic, so in my next episode I will be covering poles and throws as well as continuing to tie in inductors by talking about relays.
If you follow along with TLC, you may have noticed a pattern that after every lesson, in the following episode I make a project that involves parts or concepts from that lesson.
Next week I'll be starting work on a project for poles, throws, and relays, but I haven't settled on a project yet.
So I'm here to ask for your input! I'm looking for a project that shows off the use of either switches with multiple poles and throws or possibly makes use of a relay. Ideally the project really shows off how the switch functions. The circuit should also use fairly basic components, preferably no micro controllers or ICs. So what have you got? Lend me your ideas! Bonus for including a schematic.
If I end up using your idea for the episode, I may even send you a little something special.