This instructable is easy to build. It will help you to find out if a component you want to use is working or not. The LED lights up if the component is working properly and is off when it's not
Step 1: Components Needed
R1 = 390 Ohm/ 370 Ohm
R2 = 22K Ohm
Battery = 9V
LED=1 red better
Header Pin (3)
You should try it first on a solderless breadboard to be sure its working properly before building it as a device. To build it as a device, you will need the header Pin so you can insert the components in for testing.
Step 2: Getting Started
Step 3: Components to Be Tested
Now this device you have built can test just about lots of components as shown in the pics. The LED lights up to show its working perfectly. If it's off then the component isn't working. But mind u that with capacitors there's a charging that goes on when you connect hence the LED lights up first while it's charging and turns off when it's fully charged. So don't expect it to stay on. it just blinks.
lastly, if the LED is brighter, means higher resistance in the component and if its dimmer means lower resistance. if it doesn't light up at all then you know what's wrong.