Home / Instrumentation

Instrumentation

Maxwell Inductance Bridge Circuit

For measurement of inductance, the Maxwell Bridge shown in figure 1 can be employed. It is seen that the circuit of the Maxwell Bridge is simply a repeat of the series resistance-capacitance bridge, with the capacitors replaced by the inductors. Fig.1: Maxwell Bridge  A disadvantage of this bridge is that the …

Read More »

Series Resistance Capacitance Bridge Circuit

One disadvantage of simple Capacitance Bridge is that perfect balance of the bridge is obtained only when Cs and Cx are both pure capacitances (i.e. they have virtually no resistive components). In general, this occurs only with capacitors that have air or mica dielectrics. Capacitors with other types of dielectric …

Read More »

Capacitance Bridge Working Principle

AC bridges are used for measurement of inductances and capacitances. All AC bridge circuits are based on Wheatstone bridge. Figure 1(a) shows the circuit of a simple capacitance bridge. Cs is a precise standard capacitor, Cx is an unknown capacitance, and Q and P are standard resistors, one or both …

Read More »

Digital Multimeter Working Principle

    Fig.1: Digital Multimeter There are two main types of multimeters.  One of the first and oldest multimeters is the analog meter, (Figure 2) and the other, now more widely used meter is the digital multimeter (Figure 1). Fig.2: Analog Multimeter Analog Multimeter Analog meters are a multifunctional multimeter that …

Read More »

Wire Gauge Sizes | Circular mils

For comparison of the resistance and the size of one conductor with another, some convenient unit must be established. This unit is the mil-foot (mil-ft). a conductor will have this unit size if it has a diameter of one mil (0.001 inches) and is one foot long. The circular mil …

Read More »

Impedance Measurement Theory

The opposition that a circuit offers to the flow of AC is called impedance. By measuring the voltage and current in an AC circuit and utilizing the following equation $Z={}^{V}/{}_{I}$ We can obtain the magnitude of circuit impedance. However, it is often desirable to separate impedance into resistive and reactive …

Read More »

Ohmmeter Basic Concepts and Working Principle

Ohmmeter Definition An ohmmeter is an instrument used to measure the resistance. It is an instrument containing a voltage source and a meter directly calibrated in ohms. Series Ohmmeter One type of ohmmeter is the series ohmmeter, so called because the meter movement is in series with the source of …

Read More »

Digital Voltmeter Circuit and Working Principle

In digital voltmeters, input quantity is a voltage or is converted into a voltage. Normally, digital voltmeters are abbreviated as DVM. The process by which a DVM converts the analog input into digital output is known as analog to digital conversion. The basic conversion processes are the comparison and voltage …

Read More »

Oscilloscope Basics | What is an Oscilloscope

“Oscilloscope is most widely used to display amplitude and period of the signal as well as the shape of the wave.” Anything can be measured on the two-dimensional graph drawn by an oscilloscope. Normally, voltage is displayed on the vertical, or Y-axis and time on the horizontal, or X axis …

Read More »

Potentiometer Variable Resistor Working Principle

A potentiometer or a rheostat is an instrument used to measure and compare potentials without drawing any current from the circuit. Potentiometer Principle The potential difference across any length of wire of uniform cross section area is directly proportional to its length where a constant current flows through it. A potentiometer …

Read More »