Instructables

How to make a cheap and easy continuity tester!

Picture of How to make a cheap and easy continuity tester!
Every multimeter has a continuity tester. But what do you do when you don't have a multimeter or if it is broken and you want to test continuity of a circuit. That's right you make a continuity tester yourself. In this instructable you will learn how to make a cheap and easy continuity tester yourself.
 
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Step 1: About the 555

Picture of About the 555
This continuity tester is made from a 555 ic. I think before making this continuity tester you should first know the pinout of 555 ic. It is given in this step.

Step 2: Collecting the materials

The material that you need to make this continuity tester is found easily. The things that you need to make this continuity tester are

555 ic
39 ohms resistor
33k resistor
10k resistor
1k resistor
0.01 uf capacitor- 2 ( number 103)
Bc557 transistor
Bc547 transistor (you can also use 2n2222 or 2n3904)
Some pieces of metal to act as probes
6v dc power supply (6v battery)

Step 3: Making it!!

Picture of Making it!!
Make the whole circuit on a perfboard or pcb and put it in a box. This circuit will detect low resistances and high resistances to produce a tone from the speaker. It will detect up to 200k and the circuit automatically turns off when the probes are not used. The schematic is given in this step. All comments are welcome. The schematic and info were taken from talkingelectronics.com
blkhawk2 years ago
It would be nice to see pictures of this project made by you. How do we know that you have made this project yourself? How did you overcome problems that you encounter when building this project?
georion blkhawk2 years ago
What! Your not psychic?????
blkhawk georion2 years ago
No, I'm not. I can assume that you have not made this project yourself. Copying from somewhere else and present it as your own is called plagiarism and it is highly unethical.
http://www.555-timer-circuits.com/wailing-siren.html

Near as I can tell that article outdates this 'ible by a few months
That being said, this seems like a fun project to try. If I get around to it, I'll post a real 'ible about it