How to Check a 7805 with a Multimeter

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Have you heard of 7805? What do these numbers mean? Today’s post will talk about what a 7805 is, how it works, and how you can check it using a digital multimeter. Are you ready? Without further ado, let’s begin.

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What is a 7805? 

7805 is another voltage regulator IC (integrated circuit). It’s a member of the 78xx series. You see, the voltage source within a circuit might have variations and wouldn’t provide the fixed voltage output.

Moreover, the 7805 IC keeps the output voltage at a continuous value. Keep in mind that the “xx” in the 78xx voltage regulator suggests the fixed output voltage it’s designed to offer. 7805 offers a +5V controlled power supply. Further, capacitors’ area appropriate values could be linked at output and input pins based upon the corresponding voltage levels. 

Other varieties are 7812 and 7809, offering outputs of 12 volts and 9 volts accordingly. It’s simple to use as it has three pins, and a few external components are needed.

To explain further, 7805 is an IC utilized for voltage regulation and comes in the TO-220 version. As mentioned earlier, it belongs to the 78xx series, where xx determines the output voltage it produces.

Voltage regulation refers to the measure of voltage change between output and input. The IC 7805 does the same thing. It offers continuous output voltage whenever a range of numerous voltages is applied at the input terminal.

That component comes along with three terminals:

  • output
  • ground
  • input 

That’s known as a positive voltage regulator as it produces positive voltage to the ground terminal. Voltage regulator IC and transistor-like 7805 works similarly to offer voltage regulation. 

Voltage fluctuation is a typical practice during the implementation of different electronic projects. That component stops and overcomes that voltage fluctuation by presenting a continuous output voltage at the output terminal. 

One of the best parts about it is that it does not need any added components to set up output voltage. Further, 7805 is a compact IC that comes along with a built-in protection circuit, preventing the circuit from excessive heating. That makes a good option for circuits that draw high currents. 

The input voltage range distributed to the input terminals of this IC differs from 7 volts to 18 volts. In rare cases, it differs to seven to 35 volts, which leads to the production of the continuous output voltage of about 5 volts. 

As you can tell, there’s a big difference between the output voltage and input voltage that gets regulated. That difference is discharged as heat. You see, the surge of heat production could destroy the device and impact the overall project’s performance. 

How Does It Work?

A voltage regulator produces a fixed output voltage of a present magnitude, which stays constant irrespective of changes to its load conditions or input voltage. In the IC 7805 voltage regulator, a huge amount of energy is exhausted in the form of heat. 

The only difference in the value of output voltage and input voltage comes as heat. Hence, there will be more heat production if the difference between the output voltage and the input voltage is high. Without a heat sink, that too much heat will start a malfunction. 

What Are the Applications of a 7805 Voltage Regulator? 

A 7805 voltage regulator is utilized over a wide array of applications. Some of its uses are the following. 

  • Thermal shutdown and safe operating area protection make it perfect for different applications that involve pressure and temperature.
  • It’s the perfect option for applications supporting current at least 1.0A to 1.5A that can’t be acquired without correct heat sinking. 
  • This regulator is typically utilized for producing constant voltage output. Nevertheless, it can be modified and personalized to use for the needed voltage and current at the output.
  • Safe area compensation is another benefit you can get from using the 7805 regulators.
  • The regulator is widely used in cases where internal circuit limiting is needed. 
  • Remote control extension and UPS power supply circuit make use of this regulator. 
  • It is mainly utilized in a portable CD player and phone charger.
  • It is used in a circuit where a continuous and constant voltage is necessary. 

How Do You Check a 7805 Regulator? 

Testing input voltage

Check the voltage from the input pin to the ground when the testing voltage of a 7805 voltage regulator. That will ensure the voltage is being supplied to it. It won’t be able to output its rated regulated voltage if the regulator is not getting enough voltage.  

  1. Take your multimeter and set it in the DC voltage setting. 
  1. Take the probes and put the positive probe on the input pin of the regulator and the negative probe on the ground pin. The voltage readings must be higher than the voltage regulator is rated to output. That’s typically 1 to 2 volts higher. 
  1. The voltage regulator is getting enough voltage to regulate down if you receive a higher voltage reading.

Testing output voltage 

You should get a voltage reading of at least 5v coming out from the output of the regulator and rated to the output of 5V. The 7805 is a voltage regulator rated to output 5V, so you should read that output. 

  1. Put the same multimeter set in the DC voltage mode.
  1. Put the positive probe of your meter on the regulator’s output pin and the negative probe on the regulator’s ground pin. You should have a reading of voltage at or about the rated voltage the regulated is made for.
  1. Your voltage regulator functions and is good if the meter does read a voltage close to its rated output voltage. If not, your voltage regulator is defective and needs immediate replacement. It also means it doesn’t do the job it was created for, that is, output a regulated voltage. 

Final Thoughts

There you have it! We hope you find our guide educational and helpful. If you are not certain or have any questions in mind, feel free to ask us by leaving your thoughts in the comment section below. We would love to help you in any way we can. 

Always keep your suggestions and feedback coming, as they enable us to give you quality work, which aligns with your demands and needs!

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