Introduction:
Resistance to electricity is a force that opposes the flow of current. We use some instruments to measure this resistance in electricity Ohmmeter and multimeter are one of those instruments that measure electrical resistance in the circuit. Therefore, if you want to know the difference between ohmmeter and multimeter then you came to the right place we will discuss in this article, how they both work and how they differ and what are their functions.
What is ohmmeter?
An ohmmeter is a simple instrument used to measure electrical resistance. An electronic device measures small values of resistance in a circuit. Three types of ohmmeters calculate the values of resistance that are micro-ohmmeter, milli-ohmmeter, and mega-ohmmeter. An ohmmeter has mainly been used for electrical resistance because the ohm is the measuring unit of resistance. Moreover, it also tells us about the situation of the capacitors in the circuit.
Ohmmeter forms its circuit, so when you want to take the reading of resistance value you have to disconnect the power supply first. According to the types of ohmmeter, all resistance values from high to low have been measured in micro, milli, and mega ohmmeters. An ohmmeter consists of a current meter, battery source, and resistors.
Working of ohmmeter:
Ohmmeter apparatus consists of two test leads and one needle that is controlled by the battery of the circuit. The two test leads have shorted together in the initial, and then the needle from going from zero to the highest point, and resistance can be measured when these two test leads are detached. These two leads are connected to a battery then the battery has discharged and the needle moves to its lowest point of zero so, the resistance would be zero at that time.
Types of ohmmeter:
According to the applications of an ohmmeter, three types have given below:
1- Series type ohmmeter:
In series type, ohmmeter the component that we want to measure has connected in series, and resistor 2 has connected parallel. Therefore, when the value of resistance is zero then the current flow is high there is no barrier to current flow, when the resistance increases the flow of current slowdown. When the measuring component is detached then there is high resistance and the meter shows infinity resistance which means no flow of current. When the measuring component has connected in series then the needle of the meter moves towards the left and shows high resistance and vice versa.
2- Shunt type ohmmeter
In this type of ohmmeter, the measuring component has connected parallel with the battery in the circuit to measure the low-value resistance. Measuring component connected across the terminal A&B with battery and meter in the circuit. When the resistance of the component is high then the needle of the meter shows full-scale deflection towards the left. Therefore, there is no current in the left direction and a smooth flow of current in the right direction.
3- Multi-range ohmmeter
This multi-range ohmmeter has an adjuster to adjust the range of the resistance that we want to measure. If you want to measure the resistance below 10 then you have to adjust the resistance value to 10ohms so, that the measuring component has connected in parallel. The resistance value can be measured according to the deflection of the needle.
What is a multimeter?
An electronic multifunctional instrument multimeter uses to measure the current (AC or DC), resistance, and voltage (AC or DC). It can also act like an ohmmeter, ammeter, and voltmeter because it can measure all these three parameters. It consists of a display, power source, probes, and power supplies. This advanced electronic instrument can also measure some other parameters like temperature, capacitance, frequency, transistor gain, and voltage drop of diodes.
Working:
Multimeter instruments have two leads, probes, and three ports according to the requirement for proper measurements. The two leads are black and red, the black lead has connected to the common ports, and the red has connected to the other ports of the instrument. When you want to measure the voltage, you have to set the range of your knob; if the voltage is high, you have to set your knob up to 20V DC. For low voltages, you have to set the range up to 2V in the multimeter.
For obtaining the measurements of the required components, you have to touch the end of the probe with the end terminal of the component but be aware not to touch the end of the metal bar in the tester because it gives you an electric shock that is dangerous for you.
Types of multimeter:
The electronic multimeter has two standard types that have given below:
1- Analog multimeter:
An Analog multimeter is used to measure the voltage and current of the component. It consists of a coil meter and a pointer. The coil meter has a coil wound that is around the drum placed between the two permanent magnets. When we measure the current, it passes through the coil and the magnetic field induced between the magnets and pointer shows the deflection on the scale that is attached to the drum where a spring is also attached that controls the deflection of the pointer.
2- Digital multimeter
The most commonly used multimeter is a digital multimeter because of its accurate values. It consists of two probes negative and positive that are black and red. The Black probe is connected to the COM JACK and the red probe connects according to the user requirement that he wants to measure. So when you measure AC or DC, the given input is initially converted to voltage and then to the analog to digital converter to get the desired output.
Ohmmeter vs multimeter:
Conclusion:
The ohmmeter and multimeter both are electronic instruments used to measure the electrical resistance in the circuit but the ohmmeter only measures electrical resistance, a multimeter is multifunctional and measures the current, voltage, and resistance. In this article, we discussed ohmmeter and multimeter in all aspects and differentiate both of them completely.
