In crystal oscillators, the usual electrical resonant circuit is replaced by a mechanically viÂbrating crystal. The crystal (usually quartz) has a high degree of stability in holding conÂstant at whatever frequency the crystal is originally cut to operate. The crystal oscillators are, therefore, used whenever great stability is needed, for example, in communication transÂmitters, and […]
Hartley oscillator circuit. Hartley oscillator was invented in 1915 by the american engineer Ralph Hartley while he was working for the Western Electric company. The original design was tube based and he got a patent for it in the year 1920. In a Hartley oscillator  the oscillation frequency is determined by a tank circuit comprising
The Clapp oscillator shown in figure. is a refinement of the Colpitt’s oscillator. The single inductor found in the Colpitt’s oscillator is replaced by a series L-C combination. Addition of capacitor Ca in series with L improves the frequency stability and eliminates the effect of transistor parameters on the operation of the circuit. The
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Colpitts Oscillator An oscillator is used to produce electronic signal with oscillating periods. Eg: Sine wave, square wave etc.. Oscillators are broadly classified into two – linear oscillators and non-linear oscillators. As the name implies, linear oscillators are used to produce linear or sinusiodal waveforms. Whereas, non-linear oscillators are used to produce non-linear (non-sinusoidal output
Tuned base oscillator. Tune base oscillator is another type of transistor based LC oscillator where the tuned circuit (tank circuit) Â is placed between the base and ground of the transistor. The tuned base oscillator is also called “Armstrong oscillator” after the name of its inventor. The tuned circuit essentially consists of a transformer and capacitor
Tuned collector oscillator. Tuned collector oscillation is a type of transistor LC oscillator where the tuned circuit (tank) consists of a  transformer and a capacitor is connected in the collector circuit of the transistor. Tuned collector oscillator is of course the simplest and the basic type of LC oscillators. The tuned circuit connected at the
LC oscillators. LC oscillator is a type of oscillator where a LC (inductor-capacitor) tank circuit is used for giving the required positive feedback for sustaining the oscillations. The LC tank circuit is also termed as LC resonant circuit or LC tuned circuit. According to the Barkhausen criterion for sustained oscillations, a circuit will sustain stable
Essentials of Transistor Oscillators An oscillator must have the following three elements Oscillatory circuit or element. Amplifier. Feedback network. The oscillatory circuit or element, also called the tank circuit, consists of an inductive coil of inductance L connected in parallel with a capacitor of capacitance C. The frequency of oscillation in the circuit depends upon
How an oscillator operates ? Related Articles BASIC OSCILLATORY CIRCUITS TRANSISTOR PHASE SHIFT OSCILLATOR NEGATIVE RESISTANCE OSCILLATORS HARTLEY OSCILLATOR To know the basics of oscillators, its frequency stability, types of oscillations, different types of oscillators and so on, use the tag link – OSCILLATORS A feedback amplifier having closed-loop gain, Af greater than unity can
Related Posts OSCILLATOR OPERATION BASIC OSCILLATORY CIRCUITS CLAPP OSCILLATOR WIEN BRIDGE BRIDGE OSCILLATOR LC OSCILLATORS AND TYPES Even if an oscillator is set at an initial frequency, it cannot be maintained throughout. They keep on changing either in a uniform way or sometimes erratically. the term “frequency stability” is used to define the ability of
Related Posts DAMPED AND UNDAMPED OSCILLATIONS OSCILLATOR OPERATION TUNED BASE OSCILLATOR COLPITT’S OSCILLATOR CRYSTAL OSCILLATOR Basic Oscillator Circuit The oscillatory circuit, also called the L-C circuit or tank circuit, consists of an inductive coil of inductance L connected in parallel with a capacitor of capacitance C. The values of L and C determines the frequency
This article has two sections: One discusses criteria for selecting an oscillator while other one discusses various types of oscillations. 1. Selection of an Oscillator 2. Types of Oscillations Criteria for Selection of an Oscillator Here are the parameters that are to be noted while selecting an oscillator for a particular application. Frequency Range. The
Introduction to Oscillators An oscillator is the basic element of all ac signal sources. It generates a sinusoidal signal of known frequency and amplitude. An oscillator is one of the most basic and useful instruments used in electrical and electronic measurements. Since sinusoidal waveforms are encountered so frequently in electronic measurement work, the oscillator (sine
Types of Active Filters Butterworth, Chebyshev, Bessel and Elliptic filters. There are basically 4 types of active filters. They are butterworth, Chebyshev, Bessel and Elliptic filters. Butterworth Filter: This filter is also called as maximally flat or flat flat filter. This class of filters approximates the ideal filter well in the pass band. Frequency response curves
With the advancement in IC technology, a number of manufacturers now offer universal filters having simultaneous low-pass, high-pass, and band-pass output responses. Notch and all-pass functions are also available by combining these output responses in the uncommitted op-amp. Because of its versatility, this filter is called the universal filter. It provides the user with easy
An all-pass filter is that which passes all frequency components of the input signal without attenuation but provides predictable phase shifts for different frequencies of the input signals. The all-pass filters are also called delay equalizers or phase correctors. An all-pass filter with the output lagging behind the input is illustrated in figure. The
The bandpass filÂter passes one set of frequenÂcies while rejectÂing all others. The band-stop filter does just the opposite. It rejects a band of frequencies, while passing all others. This is also called a band-reject or band-elimination filter. Like bandÂpass filters, band-stop filters may also be classified as (i) wide-band and (ii) narrow band reject
Band Pass Filter A band-pass filter is a circuit which is designed to pass signals only in a certain band of frequencies while attenuating all signals outside this band. The parameters of importance in a bandpass filter are the high and low cut-off frequencies (fH and fl), the bandwidth (BW), the centre frequency fc, centre-frequency
Higher Order Filters From the discussion made so far on the filters, it may be concluded that in the stopband the gain of the filter changes at the rate of 20 db/decade for first-order filters and 40 db/decade for second-order filters. This means that as the order of the filter is increased, the actual stopband
In many low-pass filter applications it is necessary that the closed-loop gain is as close to unity as possible within the passband. The Butterworth filter is best suited for such applications. This filter is also called a maximally flat or flat-flat filter. Ideal and the practical frequency responses for three types of Butterworth low-pass filters
The most widely used active filters are (i)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â low-pass (ii)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â high-pass (iii)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â band-pass (iv)Â Â Â Â Â Â Â Â Â Â Â Â Â Â band-stop or band reject (also called the band-elimination or notch) and (v)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â all-pass filters. All of these filters use op-amps as the active elements and R-C networks. Although the 741 type op-amp operates satisfactorily in these filter circuits, highÂ-speed op-amps like
Active and Passive filters – A Comparison: The simplest approach to building a filter is with passive components (resistors, capacitors, and inductors). In the R-F range it works quite well but with the lower frequencies, inductors create problems. AF inductors are physically larger and heavier, and therefore expensive. For lower frequencies the inductance is to
Introduction to Filters An electric filter is a network designed to attenuate certain frequencies but pass others without attenuation. A filter circuit, therefore, possesses at least one pass band — a band of frequencies in which the output is approximately equal to the input (that is, attenuation is zero) and an attenuation band in which
Most of us take the mains ac supply for granted and use it almost casually without giving the slightest thought to its inherent shortcomings and the danger posed to sophisticated and sensitive electronic instruments/equipments. For ordinary household appliances such as incandencent lamps, tubes, fans, TV and fridge, the mains ac supply does not make much
