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78L05 Pinout: Understanding its Features and How to Use One

About 78L05 Pinout, Voltage regulators are important electrical devices that prevent your electronic circuit and electric components from getting fried. They help keep a fixed voltage despite the output impedance and input voltage changing.

This article will help you learn and determine the right 78L05 voltage regulator connections for your needs!

What is 78L05?

The 78L05 regulator is not only a positive voltage regulator but also gives out a constant output voltage. The number “78” on 78L05 shows the device provides a positive voltage. At the same time, “05” signifies the 5V constant output given by the regulator from a 12V maximum input voltage.

The 5v ensures a constant amount of power to most external components. Hence, it is included in high-current voltage regulators for a wide range of current loads.

The regulator comes in SO-98, TO-92, and SO-8 package types. Notably, the regulator undergoes energy loss in the form of heat. Therefore, using adequate heat sinking to mitigate and stop the IC from overheating.

(an automatic voltage regulator.)

78L05 Pin Configuration

The 78L05 voltage regulator has three pins that perform different functions. The below list describes each pin.

  •  Output pin regulating a 5V output voltage
  •  Ground pin connects the entire system to the ground
  •  Input pin supplying electric current to the system but with an unregulated   input voltage supply

78L05 Features

  • Firstly, the design of this regulator is to output a fixed voltage of +5v with a 5mA operating current.
  • Secondly, the varied input voltage has a high current rating, with its maximum at 30v. Therefore, this explains that the IC has a wide input supply range.
  • Thirdly, the regulator produces a maximum output current of 100mA and has thermal shutdown characteristics.
  •  The 78L05 supply circuits have a high junction temperature and a heat shutdown capability.
  • Moreover, this electrical device has inbuilt thermal overload protection and a short circuit current limiting protection.
  • Lastly, the 78L05 component comes in a TO-92 and other small packages.
voltage regulator icons

(voltage regulator icons.)

78L05 Equivalents

Notable three-terminal voltage regulator equivalent devices instead of a 78L05 include the LM7805 and the AMS7111.

78L05 Alternatives

The alternative commercial devices you can use in place of a 78L05 three-terminal voltage regulator are the LM317, LM7809, and LM117V33. In addition, the LM7806, LM7905, LM7912, and the XC6206P332MR are alternative options if needed to carry the electrical load.

Adjustable voltage regulator modules

(Adjustable voltage regulator modules)

78L05 advantage

  • Perfect for maximum load functions.
  • Improves output impedance.
  • Solves distribution problems and limits noise.
a voltage regulator on a white background

(a voltage regulator on a white background.)

78L05 Pinout: How to use 78L05?

First, connect the input pin to the voltage that requires regulation. Next, you’ll connect the ground pin to the system’s ground. Also, remember that the output pin works to regulate a voltage of 5V.

78L05 circuit diagram

(78L05 circuit diagram.)

78L05 Pinout: Circuit Explanation

You need to use the regulator in a  circuit with two capacitors on both ends of the circuit from the circuit design. The capacitors are ceramic capacitors that filter any form of noise accompanying the input voltage. One capacitor is of the 10Uf value, known as the input capacitor. At the same time, the second capacitor is the output capacitor and has a 1Uf value. Apart from its difference in values, the input capacitor handles the input inductance issues. On the other hand, the output capacitor adds stability to the circuit.

78L05 Pinout: automotive relay voltage regulator.

(automotive relay voltage regulator.)

Nevertheless, this popular voltage regulator has a feature that gets activated when the circuit temperature is higher than the junction temperature. This specific feature offers a special circuit protection capability.

78L05 Pinout: a photo of ceramic capacitors that work with the 7815 voltage regulator

(a photo of ceramic capacitors that work with the 7815 voltage regulator.)

78L05 Pinout: 78L05 Applications

  • Firstly, you can use it as a current limiter in some electronic applications.
  • Secondly, it’s used as an output booster circuit and functions as an output polarity-reversal-protection circuit.
  • Thirdly, it efficiently works as an adjustable output regulator.
  • Additionally, it serves as an important device for local on-card regulation.
  • Also, the 78L05 IC is instrumental in making logic systems and HiFi models.
  • Lastly, use the regulator as a constant +5v output regulator. Additionally, this +5v output power helps run microcontrollers and electronic sensors in most electrical projects.
78L05 Pinout: a picture of a voltage regulator

(a picture of a voltage regulator.)


The 78L5 voltage regulator belongs to the LM78XX series. Moreover, the 78L5 voltage regulators provide excellent characteristics that make them an easy-to-use, reliable electronic component.

If you’re interested in learning more about your related voltage regulator projects, contact us! Our team is always happy to answer any questions from you.

Hommer Zhao
Hi, I am Hommer, the founder of WellPCB. So far, we have more than 4,000 customers worldwide. If you have any questions, you can feel free to contact me. I really appreciate any help you can provide.