# How to convert current into voltage ?

Converting current into voltage involves using a resistor to create a voltage drop proportional to the current flowing through it. This method is commonly known as using a “shunt resistor.” By Ohm’s law, voltage (V) is equal to current (I) multiplied by resistance (R). Therefore, placing a known resistor in the path of the current allows you to measure the voltage drop across it, providing a direct correlation between the current and the resulting voltage.

To convert current to volts, you typically employ a circuit where the current passes through a resistor. The voltage developed across this resistor is directly proportional to the current flowing through it. By choosing an appropriate resistor value and measuring the resulting voltage, you can accurately determine the current value based on the relationship V = IR, where V is voltage, I is current, and R is resistance.

Converting current to voltage is often necessary to interface current-based sensors or devices with voltage-based measurement systems or analog-to-digital converters (ADCs). Many measurement instruments and control systems are designed to accept voltage inputs rather than current inputs. By converting current signals to voltage signals, compatibility is ensured between different types of devices and systems, allowing for easier integration and processing of signals in electronic circuits.

To convert a 4 to 20 mA current signal to voltage, you can use a resistor in series with the current loop. The resistor value is chosen based on the desired voltage range and the maximum current of the signal (20 mA). For example, if you use a 250-ohm resistor, the voltage developed across it would range from 1 V (at 4 mA) to 5 V (at 20 mA), according to Ohm’s law (V = IR). This voltage range corresponds directly to the 4 to 20 mA current signal, providing a linear conversion from current to voltage.

The formula for a current to voltage converter, using a resistor (R) to convert a current (I) to a voltage (V), is V = IR. Here, V represents the voltage across the resistor, I is the current flowing through the resistor, and R is the resistance value of the resistor. This simple relationship allows for accurate conversion of current signals to voltage signals in electronic circuits, facilitating measurement and control applications where voltage inputs are preferred or required.