Voltage Divider Resistor Calculator

Voltage Divider Circuit


Resistor, R2, voltage divider formula



VIN
R1
VOUT
R2=


The voltage divider Resistor calculator calculates the value of the resistor, R2, of the voltage divider network based on the value of resistor, R1, the input voltage, VIN, and the output voltage, VOUT. This resistor value of R2, is calculated by the formula, R2= (VOUT * R1)/(VIN - VOUT) .

To use this voltage divider resistor calculator, a user must enter the value of the input voltage, VIN, the value of resistor R1, and the output voltage, VOUT, and click the 'Calculate' button. The voltage output result will then be calculated and automatically displayed. The result of this output voltage is calculated in unit volts (V).

Voltage dividers are very common and used very often in circuits. Many times in circuits, different levels of voltage must be allocated to different parts of a circuit. To do this, a voltage divider circuit, such as that shown above, can be used. This can divide the input voltage that a circuit receives and allocate it accordingly and as needed to different parts of the circuit. For example, a circuit may receive 10V as input. However, one chip in the circuit may need 7 volts, while another chip in the circuit only needs 3 volts. We can allocate these voltages to the different chips by a voltage divider. If we make one resistor have a value of 3KΩ and the other resistor have a value of 7KΩ, this will allocate the 10 volts into 3V and 7V. Thus, the resistor values control the voltage allocation.

Example Calculation

If resistor R1 is 1KΩ and resistor VIN is 12V and the output voltage is 8V, what is the value of resistor, R2?

R2= (VOUT * R1)/(VIN - VOUT)= (8V * 1KΩ)/(12V - 8V)= 2KΩ

So R2= 2KΩ.

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