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LM7912 Negative Voltage Regulator

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Pin Configuration:

Pin Number

Pin Name

Description

1

Ground (Gnd)

Connected to Ground

2

Input (V+)

Unregulated Input Voltage

3

Output (Vo)

Outputs Regulated -12V

 

7912 Regulator Features:

  • 12V Negative Voltage Regulator
  • Minimum Input Voltage is -14.5V
  • Maximum Input Voltage is -27V
  • Peak Output Current is 2.2A
  • Average Output Current is upto 1A
  • Internal Thermal Overload and Short circuit current limiting protection is available.
  • Available in TO-220 package only.

Note: Complete Technical Details can be found at the 7912 datasheet given at the end of this page.

 

LM 7912 Equivalent Voltage Regulator ICs:

LM7905, LM7912, LM7915, LM7918

 

Where to use LM7912:

LM7912 belongs to the family of Voltage regulators. The name “79” indicates negative and the term “12” indicates the voltage. So “7912” means that this IC will regulate a negative 12V for your projects. You can also check on 78 series for positive voltage regulators.

When you are designing an analog circuit, the circuit might need negative voltage either as a power source or as a reference voltage. In both cases 7912 will be an ideal choice when you need a negative 12V. The output current of this IC is upto 1A, however with appropriate heat sink the datasheet says that a peak current of 2.2A can be achieved through this IC.

 

How to use LM7912 Voltage regulator:

The LM7912 is a -12V Voltage regulator IC. Meaning it will provide a constant output voltage of -12V when the input voltage is between -14.5V to -27V. A very basic Voltage regulator circuit is shown below.

 circuit diagram of LM7912 Negative Voltage Regulator

I have used a Battery to power the IC, but you can use any power source but notice that the supply voltage should be negative. Hence, I have interchanged the polarity of the battery. The Input and output capacitors C1 (10uF) and C2 (1uF) are used to filter noise from the input and the output voltage respectively. The negative output voltage is obtained from the Vo (3rd Pin) which is also read using a Multimeter. The value of the capacitors need not be the exact values, you can use the closest value you have got.

There are many other ways in which the IC can be used based on your application. The circuit diagram for those can be found at the datasheet given at the end of this page.

 

LM7912 Applications:

  • Constant -12V output regulator to use as power or reference voltage for analog and digital circuits.
  • Current Limiter for certain applications
  • Regulated Dual Supply
  • Output Polarity-Reversal-Protection Circuit

 

2D model of the component:

 2D model of LM7912 Negative Voltage Regulator