After looking a lot for a case that would be small enough to fit inside a pocket, but big enough to hold all the electronics.
So, this tester has the following functions:
Step 1: Materials
3 LEDs the color you want (mine were 2 yellow and 1 green);
Battery pack (at least 3V to the LEDs)
A 1000 ohm resistor,
1 SPST switch,
1 2 pin connector,
1 3 pin connector,
A neat case (mine was a sewing button case)
To me, since I had all the materials laying around I only purchased the case, that was 0.90€, so it costed me 0.90€ and I got 6 sewing buttons (no idea what I can make with them... yet)
Step 2: The Battery Pack
Step 3: Electronics
Step 4: Make It Look Neat
Step 5: Done and How to Use
How to use:
Continuity - set the switch to C and touch the probes into what you want to know if has continuity.
Polarity - set the switch to P an touch the probes into the poles. The X LED will light up if the polarities are wrong (the red probe is plugged to the - pole and vice versa) and the "right" LED will light up if the polarities are correct (red to + and vice versa)
LED - touch the LED's leads to the side of the 2 pin connector or plug them into the pin holes and watch if it lights up or not. If it does, the LED works and you foud it's polarity. If not switch places. If it lights up you have your polarity, if not, it's blown.
Transistor - use the connector the same way as the LEDs, but the indicator is the OK LED. The indicator is the round part. If it is facing forward, it is one type, if is the other way, it's the other type.
Diode - use the same way as Continuity or in the transistor tester