Definition: An op-amp detector that has the ability to detect the change from positive to negative or negative to a positive level of a sinusoidal waveform is known as a zero crossing detector. More specifically, we can say that it detects the zero crossing of the applied ac signal. It is basically a voltage comparator whose output changes when the input signal crosses the zero of the reference voltage level. Thus it is named so. It is also known to be a square wave generator as the … [Read more...] about Zero Crossing Detector
Relaxation Oscillator
Definition: A relaxation oscillator is basically a non-linear oscillator that has the ability to generate a non-sinusoidal periodic waveform at its output. Such as triangular wave, square wave etc. These are also known as non-sinusoidal waveform generators. A relaxation oscillator operates in such a way that it generates oscillations by charging the capacitor and quickly discharging it after attaining a pre-determined threshold voltage. The figure below will help you to understand the … [Read more...] about Relaxation Oscillator
Anderson’s Bridge
Definition: Anderson’s Bridge is an AC bridge that determines the self-inductance of an inductor in the circuit. This bridge offers highly accurate output and is an advancement of Maxwell’s inductance capacitance bridge. By Anderson's bridge, one can measure inductance by utilizing other circuit components like resistors and capacitor. In Maxwell’s bridge, the inductance is calculated by comparing it with a standard variable capacitance. In this article, we will discuss the construction, … [Read more...] about Anderson’s Bridge
Potentiometer
Definition: Potentiometer is an instrument that is used the determine the potential (voltage) between two points by performing a comparison with a known voltage. Basically, in order to do so, a manual variation in resistance is performed so as to control the current flow thereby determining the required voltage. Potentiometers are normally abbreviated as POT and are nothing but variable resistors that measures the emf between two existing points. The circuit of a potentiometer provides the … [Read more...] about Potentiometer
Phase Modulation (PM)
Definition: Phase modulation is another type of angle modulation in which the phase of the carrier wave is changed according to the amplitude (magnitude) of the message (modulating) signal. In phase modulation of an analog signal, the phase change is a continuous back and forth movement. While in case of digital signal there exist an abrupt change in the phase of the carrier signal. The phase modulation of the digital signal is generally known as phase shift keying. The process of phase … [Read more...] about Phase Modulation (PM)
Frequency Modulation (FM)
Definition: A category of angle modulation in which the frequency of the carrier wave is changed according to the amplitude of the message signal is known as frequency modulation. It is abbreviated as FM and is a widely used analog modulation technique. One can modulate a signal by varying the amplitude of the carrier signal according to the message signal, which we commonly knew as amplitude modulation (AM). The implementation of AM is simple. However, it possesses various … [Read more...] about Frequency Modulation (FM)
Instrumentation Amplifier
Definition: A special type of amplifier that is used to amplify signals of extremely low-level is known as Instrumentation Amplifier. It is basically a differential amplifier, that performs amplification of difference of input signal. It has high CMMR, offers high input impedance and consumes less power. CMMR stands for common mode rejection ratio, it is the ability to reject unwanted signals. It is also known as data amplifier. Nowadays, it has become an elemental part of modern … [Read more...] about Instrumentation Amplifier
Amplitude Modulation
Definition: Amplitude Modulation is a technique by which the amplitude of the carrier wave is changed according to the signal wave or modulating signal. Among various modulation schemes, amplitude modulation is the simplest and oldest modulation technique. Basically, the information that is carried by the low frequency modulating signal is superimposed on the carrier wave of high frequency by varying the amplitude of the carrier. Thus it is termed as amplitude modulation. Theory of Amplitude … [Read more...] about Amplitude Modulation
Difference between BJT and JFET
The crucial difference between BJT and JFET is that BJT is a bipolar device while JFET is a unipolar device. It is so because the operation of BJT is dependent on injection and collection of minority charge carriers that includes both electrons and holes. As against JFET is majority carrier device, thus termed as unipolar. Another major difference between BJT and JFET is that BJT falls under current controlled device category whereas JFET falls under voltage controlled device category. We … [Read more...] about Difference between BJT and JFET
Bandpass Filter
Definition: A bandpass filter (BPF) is an electronic circuit that passes a certain band of frequency without attenuation. The particular band of frequency passes by the filter is known as passband. The important parameters that have to be considered in a BPF are the low and high cut-off frequency, centre frequency along with bandwidth and selectivity. Bandpass filters are basically of two types: Active BPF and Passive BPF. An active bandpass filter requires an external power supply and … [Read more...] about Bandpass Filter