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7809 Voltage Regulator

LM7809 is a fixed-voltage integrated-circuit voltage regulator designed for a wide range of applications. The L7809 voltage regulator provides 9V Positive voltage as output and can provide local on-card regulation, eliminating the distribution problems associated with single-point regulation. Although designed primarily as a fixed voltage regulator, but it can be used with external components to obtain adjustable voltage. 


LM7809 Pinout Configuration

Pin Number

Pin Name



Input (V+)

Unregulated Input Voltage



Connected to Ground


Output (Vo)

Outputs Regulated +9V


L7809 Regulator Features

  • 9V Positive Voltage Regulator
  • Minimum Input Voltage is 11V
  • Maximum Input Voltage is 35V
  • Output Current: 1.5 A
  • PSRR / Ripple Rejection: 55 dB
  • Output Type: Fixed
  • Internal Thermal Overload and Short circuit current limiting protection is available.
  • Junction Temperature maximum of 125 degree Celsius
  • Available in TO-220, TO-3 and KTE package


Note: Complete Technical Details can be found in the 7809 datasheet given at the end of this page.


L7809 Voltage Regulator Equivalent

LM7806, LM7824, LM7815, LM7812, LM317, LM7905, LM7912.


Brief Description of 7809 Voltage Regulator IC

Voltage regulators are very common in electronic circuits. They provide a constant output voltage for a varied input voltage. The name 7809 signifies two meanings, “78” means that it is a positive voltage regulator and “09” means that it provides 09V as output.


The output current of this IC can go up to 1.5A. But the IC suffers from heavy heat loss hence a Heat sink is recommended for projects that consume more current.


 L7809 as +9V Voltage Regulator

This is a typical application circuit of the 7809 IC. We just need two capacitors of value 0.33uf and 0.1uf to get this IC working. The input capacitor 0.33uF is a ceramic capacitor that deals with the input inductance problem and the output capacitor 0.1uF is also a ceramic capacitor that adds to the stability of the circuit. These capacitors should be placed close to the terminals for them to work effectively. Also, they should be of a ceramic type, since ceramic capacitors are faster than electrolytic.

 L7809 Application Circuit


 7809 Applications

  • Constant +9V output regulator to power microcontrollers and sensors in most of the projects
  • Adjustable Output Regulator
  • Current Limiter for certain applications
  • Regulated Dual Supply
  • Output Polarity-Reversal-Protection Circuit


2D model of L7809 Voltage Regulator

L7809 Voltage Regulator 2D Model is given below:

Dimensions of L7809

L7809 Voltage Regulator's Dimensions

Component Datasheet

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