Distinguish between a potentiometer and a voltmeter.

A potentiometer and a voltmeter are both electrical measuring instruments, but they serve different purposes and have distinct characteristics. Here's how they differ:

Potentiometer:
A potentiometer is a variable resistor with three terminals. It is primarily used to measure or control voltage or potential difference in a circuit. The main features of a potentiometer are:

Variable Resistance: A potentiometer allows you to vary the resistance across its terminals manually. By adjusting the position of a sliding contact (wiper) along a resistive element, you can change the ratio of the resistance on either side of the wiper. This property makes it useful for voltage division and controlling voltage levels.

Measurement Principle: Potentiometers work based on the principle of voltage division. By connecting a potentiometer in a circuit and measuring the voltage across the terminals or the position of the wiper, you can determine the voltage or the relative position of the wiper.

No Display: Potentiometers typically do not have a built-in display to directly read the voltage. Instead, you need to connect an external voltmeter or use other measuring techniques to determine the voltage value.

Voltmeter:
A voltmeter is an instrument specifically designed to measure the potential difference or voltage across two points in an electrical circuit. The key characteristics of a voltmeter are:

Fixed Resistance: Unlike a potentiometer, a voltmeter has a fixed resistance. It is designed to have a high resistance so that it draws minimal current from the circuit under measurement, ensuring accurate voltage readings without affecting the circuit significantly.

Measurement Range: Voltmeters are available in various ranges to measure different voltage levels accurately. They can be analog (needle-based) or digital (numeric display) and may offer multiple voltage scales or ranges to accommodate different voltage levels.

Built-in Display: Voltmeters have an integrated display, which can be analog or digital, to directly indicate the measured voltage value. The display eliminates the need for external instruments to read the voltage.

Series Connection: To measure the voltage across a circuit component, a voltmeter needs to be connected in parallel with that component. It is connected in series with a circuit to measure the potential difference across specific points.

In summary, a potentiometer is a variable resistor primarily used for voltage division and control, while a voltmeter is a dedicated instrument for measuring voltage across two points in a circuit. The potentiometer's resistance can be manually adjusted, and it does not have a built-in display, whereas a voltmeter has a fixed resistance, a built-in display, and is specifically designed for voltage measurement.