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Adjustable Voltage Power Supply with LM317 and Digital Voltmeter Display

Image of Adjustable Voltage Power Supply with LM317 and Digital Voltmeter Display

Circuit Documentation

Summary of the Circuit

This circuit appears to be a power supply unit that takes an AC input from a power transformer, rectifies it using a bridge rectifier, filters the output with electrolytic capacitors, and then regulates the voltage using an LM317 voltage regulator. The output voltage can be adjusted using potentiometers, and the final output is displayed on a 7-segment panel voltmeter. Additionally, there is an LED indicator in the circuit. The circuit does not include any microcontroller code.

Component List

Power Transformer (220V to 24V)

  • Description: A transformer used to step down the voltage from 220V AC to 24V AC.
  • Pins: 2 - Primary, 1 - Primary, 3 - Secondary, 4 - Secondary

AC Supply

  • Description: Provides the input AC voltage to the circuit.
  • Pins: +ve, -ve

Bridge Rectifier

  • Description: Converts AC voltage to DC voltage.
  • Pins: Source_in-, source_out-, source_out+, source_in+

Electrolytic Capacitor (1)

  • Description: Filters the rectified DC voltage.
  • Capacitance: 0.001 Farads
  • Pins: -, +

LM317 Voltage Regulator

  • Description: Regulates the output voltage to a desired level.
  • Pins: Adj, V_out, V_in

Resistor (1)

  • Description: Sets the output voltage level in conjunction with the LM317.
  • Resistance: 442 Ohms
  • Pins: pin1, pin2

Electrolytic Capacitor (2)

  • Description: Provides additional filtering for the regulated DC voltage.
  • Capacitance: 0.00022 Farads
  • Pins: -, +

Potentiometer (1)

  • Description: Allows for adjustment of the output voltage.
  • Pins: GND, Output, VCC

Terminal PCB 2 Pin

  • Description: Provides a connection point for external devices or testing.
  • Pins: Pin A, Pin B

Potentiometer (2)

  • Description: Another potentiometer for voltage adjustment.
  • Pins: GND, Output, VCC

LED: Two Pin (red)

  • Description: Indicates the presence of voltage or power status.
  • Pins: cathode, anode

Resistor (2)

  • Description: Limits the current through the LED.
  • Resistance: 1800 Ohms
  • Pins: pin1, pin2

7-Segment Panel Voltmeter

  • Description: Displays the output voltage of the circuit.
  • Pins: V+, V-

Comments

  • Description: Non-electrical components used for annotations in the circuit design.

Wiring Details

Power Transformer (220V to 24V)

  • 3 - Secondary connected to Bridge rectifier Source_in-
  • 4 - Secondary connected to Terminal PCB 2 Pin Pin A
  • 2 - Primary connected to AC Supply +ve
  • 1 - Primary connected to AC Supply -ve

AC Supply

  • +ve connected to Power Transformer 2 - Primary
  • -ve connected to Power Transformer 1 - Primary

Bridge Rectifier

  • Source_in- connected to Power Transformer 3 - Secondary
  • source_out+ connected to LM317 Voltage Regulator V_in, Electrolytic Capacitor (1) +
  • source_out- connected to Electrolytic Capacitor (2) -, Potentiometer (2) Output

Electrolytic Capacitor (1)

    • connected to Bridge rectifier source_out+, LM317 Voltage Regulator V_in
    • connected to Potentiometer (2) Output

LM317 Voltage Regulator

  • V_in connected to Bridge rectifier source_out+, Electrolytic Capacitor (1) +
  • Adj connected to Potentiometer (1) VCC, Resistor (1) pin1
  • V_out connected to Electrolytic Capacitor (2) +, Resistor (1) pin2, 7-Segment Panel Voltmeter V+

Resistor (1)

  • pin1 connected to LM317 Voltage Regulator Adj, Potentiometer (1) VCC
  • pin2 connected to LM317 Voltage Regulator V_out, Electrolytic Capacitor (2) +

Electrolytic Capacitor (2)

    • connected to LM317 Voltage Regulator V_out, Resistor (1) pin2, 7-Segment Panel Voltmeter V+
    • connected to Bridge rectifier source_out-, LED: Two Pin (red) cathode, 7-Segment Panel Voltmeter V-

Potentiometer (1)

  • VCC connected to LM317 Voltage Regulator Adj, Resistor (1) pin1
  • Output connected to Potentiometer (2) VCC

Terminal PCB 2 Pin

  • Pin A connected to Power Transformer 4 - Secondary

Potentiometer (2)

  • VCC connected to Potentiometer (1) Output
  • Output connected to Electrolytic Capacitor (1) -

LED: Two Pin (red)

  • cathode connected to Electrolytic Capacitor (2) -
  • anode connected to Resistor (2) pin1

Resistor (2)

  • pin1 connected to LED: Two Pin (red) anode
  • pin2 not connected in the provided net list

7-Segment Panel Voltmeter

  • V+ connected to LM317 Voltage Regulator V_out, Electrolytic Capacitor (2) +
  • V- connected to Electrolytic Capacitor (2) -, LED: Two Pin (red) cathode

Documented Code

No code has been provided for any microcontrollers in the circuit. Therefore, this section is not applicable to the current documentation.