How to Make Polarity Protection Circuit

In this project, we are going to teach you making a polarity protection circuit. Polarity protection circuit is an internal circuit that ensures that the device is not damaged if the power supply polarity is reversed.

The circuit cut’s power to the sensitive electronic circuits in the transmitter or transducer. The outlet with reverse polarity can cause some items to be electrically charged at all times.

A direct bias diode placed in the circuit, which will make it only conducts when the polarity is connected correctly. The use of Schottky diodes is recommended, since the voltage drop in these is less.

We often refer to the polarity between different points in the circuit. The polarity protection circuit is very important for determining the direction of current flow.

The article is being published in collaboration with JLCPCB. They supply high quality PCBs at a very reasonable price. They also can provide SMT circuit assembly.

The final circuit diagram and design can be seen above. We also thank to our sponsor JLCPCB (https://jlcpcb.com/RTA) for sponsoring us PCB for this project.

Thanks To JLCPCB.

$2 for 1-4 Layer PCBs.

Get SMT Coupons - https://jlcpcb.com/RTA

To make this polarity protection circuit, we might need some electronics component. Those component lists have to been given below.

Component List :

1. PCB – made by JLCPCB

2. Rectifier Diode – 1N 5399

3. Relay – 12v

4. LED (red and green)

5. Resistor - 1 KΩ *2

6. Filament Bulb – 12v

7. Power Source – DC 12v

The schematic of polarity protection circuit along with the PCB layout can be seen above. Power supply don’t included with the circuit. You can use any 12 battery for this project. 

Relays can be classified into different types depending on their functionality, structure, application etc. We listed out some of the common types of relays here.

• Electromagnetic
• Latching
• Electronic
• Non-Latching
• Reed
• High-Voltage
• Small Signal
• Time Delay
• Multi-Dimensional
• Thermal
• Differential
• Distance
• Automotive
• Frequency
• Polarized
• Rotary
• Sequence
• Moving Coil
• Buchholz
• Safety
• Supervision
• Ground Fault

Relays are used to protect the electrical system and to minimize the damage to the equipment connected in the system due to over currents/voltages. The relay is used for the purpose of protection of the equipment connected with it.

These are used to control the high voltage circuit with low voltage signal in applications audio amplifiers and some types of modems.

These are used to control a high current circuit by a low current signal in the applications like starter solenoid in automobile. These can detect and isolate the faults that occurred in power transmission and distribution system. Typical application areas of the relays include

• Lighting control systems
• Telecommunication
• Industrial process controllers
• Traffic control
• Motor drives control
• Protection systems of electrical power system
• Computer interfaces
• Automotive
• Home appliances

To make this circuit, we need to assemble relay with the PCB. Then we connect diode negative terminal with 4no leg of relay as the circuit diagram. And we connect diode positive terminal with 5no leg of relay. To make this circuit, we need to assemble relay with the PCB. Then we connect diode negative terminal with 4no leg of relay as the circuit diagram. And we connect diode positive terminal with 5no leg of relay.

We are using 1 KΩ resistor to make this circuit. We connect this resistor one terminal with 3no leg of relay and connect another 1 KΩ resistor with 2no terminal of relay.

Since, it is a polarity protection circuit. We are using two different color LED light. One is red color and the other is green color LED light. We connect red color led light negative terminal with 1 KΩ resistor, that is connected with 2no terminal of relay. Then the led other terminal will be connected with 3no terminal of relay.

Now we connect our green color LED light. We connect this, green color LED light negative terminal with 1 KΩ resistor, that’s other terminal is connected with 3no terminal of relay and the led positive leg with 5no terminal of relay.

For reverse polarity protection, we are using a DC-12v filament bulb. We connect this bulb with 1no terminal of relay and another terminal with 3no terminal of relay.

Neat and perfect soldering is an important part for all kind of PCBs. Since soldering, you should remember that, there should not be any kind of short circuit connection. After soldering all leg, we cut-off the extra leg of all electronics component.

We also can use liquid PCB cleaner to clean the PCB board.

For power supply, we are using DC 12v. You can use 12v battery or can use the power supply, that can provide DC 12v. Be careful about the power supply, because if you use more than DC-12v, then led light will blown away and the circuit may damage also.

Our circuit, is now completely ready for use. Now just plug-in the power supply and make you safe from reverse polarity. 

Again thanks to JLCPCB for best quality PCBs.

If you complete design of your PCBs, then it is time to order PCBs. To order best quality PCBs, just visit JLCPCB and click on the “QUOTE NOW” button.

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