Constant Current Source Calculator

1. Input parameters

Desired current value: Iout=  mA

Q1 dissipated power:Ptot= mW

Supply voltage E1= V
2. Circuit diagram
3. Output results


R1= kOhm
R2= kOhm
R3= kOhm
Ro= kOhm
Px= mW
warn:

What is a Constant Current Source Calculator?

A Constant Current Source Calculator is a tool used to calculate the necessary components (such as resistors and voltage sources) required to build a constant current source circuit. A constant current source provides a fixed current to a load, regardless of the voltage across it or changes in the load resistance. This is essential in applications where precise and stable current is required, such as LED drivers, battery charging circuits, and sensor applications.

The basic formula for a constant current source is:

Where:

  • I = Desired current (A)
  • V_supply = Supply voltage (V)
  • V_reference = Voltage across a reference component (e.g., a diode, transistor, or resistor)
  • R = Resistance (Ω) needed to set the current.

Why Use a Constant Current Source Calculator?

  • Accurate control of current for sensitive circuits (e.g., LEDs, lasers).
  • Simplifies circuit design by calculating necessary components quickly.
  • Ensures consistent operation of components, particularly in circuits where voltage fluctuates but current must remain stable.
  • Prevents over-driving components (e.g., LEDs) that can be damaged by excess current.

How to Use a Constant Current Source Calculator?

  1. Enter the supply voltage (V_supply) — the voltage from your power source.
  2. Enter the voltage across the reference component (V_reference), which could be a diode, transistor, or other reference component.
  3. Choose the desired current (I) for your application.
  4. The calculator computes the necessary resistance (R) to achieve the constant current based on your input parameters.
  5. You can also use the calculated resistance to select the appropriate resistor for your circuit or design the entire current source circuit.

When to Use a Constant Current Source Calculator?

  • When designing LED drivers for constant brightness in a wide range of operating conditions.
  • In battery charging circuits, where constant current is needed for optimal charging.
  • For sensitive sensors that require a precise current for accurate readings.
  • In laser diode applications where current stability is critical to performance and longevity.
  • When working with analog circuits or test equipment that require a stable current supply.