Hello Guys! I am back with another instructable.

In electronics, a continuity tester is a very important tool. It helps you to troubleshoot your circuit and find faults in it. The basic idea is that the device consists of two probes. When the two probes come in contact the buzzer makes a sound and the LED glows.

Step 1: Required Hardware

The above image shows the required components for making continuity tester.

The following components have been used:

1. X3 1K Resistor(R1,R2,R3)

2. x1 DC Jack ( 12V )

3. x1 2Pin Connector

4. x2 NPN Transistor (BC547)

5. x2 Red LED

6. x1 9V battery

7. x1 Buzzer

Step 2: Making the Circuit in Breadboard

The above image shows all components assembled on the breadboard. I have used a 9v battery for input supply when the two wires are in contact the buzzer will make a sound and led will glow. The left image shows that two wires are not in contact, the right image shows the two wires are in contact then led is glowing and buzzer making sound.

Step 3: Circuit Schematic & Working

The above image shows the circuit schematic of continuity tester using Eagle software.

A simple electronics circuit can be built using a couple of transistors and few passive components, we can power up this circuit using a 9v battery or 9v DC adapter. The circuit basically is an oscillator with a buzzer connected at its output. It will produce a particular audio tone depending upon the resistance of the circuit under test connected across its testing probes. Touch the two probes buzzer will make sounds and LED glow.

Step 4: PCB Design

The image shows the circuit PCB Design of Short Circuit Detector using Eagle software

Parameter consideration for PCB design

1. Trace width thickness is a minimum of 8 mil.

2. The gap between plane copper and copper trace is a minimum of 8 mil.

3. The gap between a trace to trace is a minimum of 8 mil.

4. Minimum drill size is 0.4 mm

5. All the tracks which have current path need thicker traces

Step 5: Uploading Gerber on LionCircuits

After testing the circuit in a breadboard, we can draw the PCB Schematic with any software as per your convenience. Here I have my own design and Gerber file. After you generate the Gerber file you can upload it onto LIONCIRCUITS and place your order. I order my PCBs from LionCircuits because they provide cheaper prices and high-quality PCBs in just 5 days.