pH Measurement Methods: pH is defined as the negative logarithm of the active hydrogen ion. It is a measure of the acidity or alkalinity of an aqueous solution. The pH scale runs from 0 – 14, with pH 7, the neutral point, being the pH of pure water at 25°C. The lower the pH value, …
Megger Circuit Diagram: Another common method of measuring resistances above 50 M Ω is the Megger Circuit Diagram (megaohmmeter) shown in Fig. 10.23(a). This instrument is used to measure very high resistances, such as those found in cable insulations, between motor windings, in transformer windings, etc. Construction and Working Principles: Normal (shop) VOMs do not …
Transistor Tester and its characteristics: The term Transistor Tester (or analyser) used in this text is for instruments giving quantative measurements of transistor parameters. The tester should be able to provide direct readings for at least two important measurements, such as: A value for the forward gain in the common emitter configuration (hFE for ac gain …
Automatic Bridge Circuit: The bridges discussed so far require that the controls be adjusted for balance after each capacitor (or other devices being tested) is connected to the bridge. In effect, they are manual. In recent years a number of automatic bridges have been developed. These Automatic Bridge Circuit provide an automatic readout without adjustment …
RX Meter Circuit in Measuring Instruments: An RX Meter Circuit in Measuring Instruments is used to measure the separate resistive and reactive components of a parallel Z network. It is especially useful in the design of RF tank circuits but can be used with any parallel “Z”. The basic circuit of a typical RX meter …
LCR Bridge: Basic LCR Bridge (Skeleton Type) : A simple bridge for the measurement of resistance, capacitance and inductance may be constructed with four resistance decades in one arm, and binding post terminals to which external resistors or capacitors may be connected, to complete the other arms. Such a skeleton arrangement is useful in the …
Q Meter: The overall efficiency of coils and capacitors intended for RF applications is best evaluated using the Q value. The Q Meter is used to measure some electrical properties of coils and capacitors. The Q Meter Working Principle is based on series resonance; the voltage drop across the coil or capacitor is Q times …
Vector Impedance Meter (Direct Reading): If some knowledge of the reactive and resistive factors is needed, in addition to obtaining a direct reading of the magnitude of the impedance (Z), a test method for determining the Vector Impedance Meter may be employed. This method determines Z in polar form, that is, it gives the magnitude IZI …
What is Phase Sensitive Detector or Phase Meter Circuit?: Figure 10.4 shows a Phase Sensitive Detector or Phase Meter Circuit for comparing an ac, signal with a reference signal. The Phase Sensitive Detector Circuit produces a rectified output, which is fed to a dc meter, to illustrate clearly that the output of the phase sensitive …
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Stroboscope Working Principle: The stroboscope working principle uses a high intensity light which flashes at precise intervals. This light may be directed upon a rotating or vibrating object. The stroboscopic effect is apparent when the rotational or vibratory speed is in a proper ratio with the frequency of the light flashes. Most stroboscope working principle …