Estimated reading time: 3 minutes
What Is a Voltage Divider?
A voltage divider is a basic circuit that turns a higher voltage into a lower one. It uses two resistors connected in series. The input voltage is spread across both resistors, and the output is taken from the connection point between them. In this way, the circuit “divides” the voltage.
Think of it like pouring water from a full glass into two smaller glasses. The water is the voltage, and the glasses are the resistors. How much water each glass holds depends on its size. In the same way, a larger resistor takes a bigger share of the voltage, while a smaller one takes less.
Voltage Divider Calculator
V_in ---[ R1 ]--- V_out ---[ R2 ]--- GND
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How It Works
A voltage divider works with basic math. We use Ohm's Law. It states that voltage is current times resistance. In a circuit with resistors in a line, the current is the same for all of them. The total resistance is R1 plus R2. So, we find the current. We divide the input voltage by the total resistance.
The output voltage is the current times R2. This gives us the main formula. V_out = V_in * (R2 / (R1 + R2)). This formula shows us the part of the voltage we get. The part we get depends on the size of the resistors.
Why You Need One
Voltage dividers are very useful. They help to make a new voltage level. Many parts in a circuit need a certain voltage. A voltage divider can provide that voltage. This is an easy way to get a new voltage level.
Voltage dividers can also read data. Some sensors change their resistance. For example, a light sensor changes its resistance with light. When its resistance changes, the output voltage of the divider changes. We can measure this change. This tells us what the sensor sees. A light sensor will have a low voltage in the light. It will have a high voltage in the dark.
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FAQ
Yes, a voltage divider does use power. The resistors get hot. This heat is lost power. This is why you should not use a voltage divider for things that need a lot of power. They are best for signals or small needs.
You can use a voltage divider with a DC power source. But you must not use it for things that need a lot of power. For high-power needs, you should use a power supply. A power supply is a different kind of circuit.
A load is a part that you connect to the output. The load takes power from the divider. A load changes how the divider works. It changes the total resistance. If you use a load, you must change the formula. The formula must now include the load's resistance.
In a voltage divider, the input voltage is shared between the two resistors. The total voltage appears across both of them, but the output is taken from just one resistor. Because of this split, the output voltage is always less than the input voltage.
A potentiometer is a type of voltage divider. It is a resistor with a part that moves. You can turn a knob. This changes the resistance. So, you can change the output voltage. People use potentiometers to change volume or brightness.