Introduction: How to Use 7809 Voltage Regulator?

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Hello Friend,

Today, I will guide you through creating a voltage control circuit. With this circuit, we can transform up to 35V DC into a stable 9V DC using only a 7809 Voltage Regulator.

Let's begin,

Supplies

Components needed:

  1. Voltage regulator - 7809 x1
  2. Capacitor - 63V 470uF x1 {I'm using a 25V 470uF capacitor as I'm providing a 17V DC Input.}
  3. Capacitor - 16V/25V/63V 100uF x1
  4. Input Power Supply voltage in DC - Input voltage < 35V {Input Voltage should be less than 35V DC}
  5. Connecting wires
  6. Clippers

Step 1: 7809 Voltage Regulator Pins

This image illustrates the pins of the voltage regulator.

  • Pin-1 is Input,
  • Pin-2 is GND (Ground), and
  • Pin-3 is Output.

Step 2: Connect 470uF Capacitor

Solder the +ve pin of the 470uF electrolytic capacitor to the Input pin/Pin-1 of the voltage regulator and

Solder the -ve pin of the capacitor to the GND Pin of the Voltage regulator, as shown in the picture.

NOTE: The capacitor voltage should be greater than the Input voltage. So, connect a 63V 470uF capacitor in parallel with the input power supply, as I connected in the picture. However, I'm using a 25V 470uF capacitor here because I'm providing a 17V input, which is less than the capacitor's voltage.

Step 3: Connect 100uF Capacitor

Next, solder the +ve pin of the 100uF electrolytic capacitor to the Output pin of the voltage regulator and

Solder the -ve pin of the capacitor to the GND Pin of the voltage regulator, as shown in the picture.

Step 4: Connect Clipper Wire for 9V Output Power Supply

Now, connect clip wires to obtain a constant 9V DC output from this circuit.

Solder the +ve output wire to the Output pin of the voltage regulator and

Solder the -ve output wire to the GND Pin of the Voltage regulator, as shown in the picture.

Step 5: Connect Input Power Supply Clip

Now that our circuit is ready, connect the input power supply wire to this circuit.

Connect the +ve clip of the Input voltage to the +ve pin of the 470uF capacitor and

Connect the -ve clip to the GND Pin of the voltage regulator.

NOTE: We can provide an Input Power supply voltage up to 35V DC to this circuit.

Step 6: Reading

Now, as depicted in the above pictures:

  • Picture-1) - I provided a 17.6V DC Input, and we obtained a constant 9V Output from this circuit, as seen in picture-2.

NOTE 1: If we increase the input voltage, the output voltage will remain the same, i.e., 9V DC.

This is how we can create a circuit to obtain a constant 9V Power supply using a 7809 Voltage regulator.

NOTE 2: Add a heatsink if the 7809 Voltage regulator gets heated.