Adjustable Voltage Regulators SomeÂtimes variable voltage is required and under such a situation adjustable voltage regulator is used. A number of IC regulators, like LM 317, LM 338, and LM 350, are adjustable regulators. They have maximum load currents from 0.10 to 1.5 A. For example, the LM317 is a three terminal positive voltage regulator, […]
5Volts to 24volts Voltage Regulators using 78XX series IC 15 volts Power Supply The series 7800 regulators provide eight voltage options, ranging from 5 to 24 V. These ICs are designed as fixed voltage regulators and with adequate heat sinking can deliver output currents in excess of 1 A. Although these devices do not require
A voltage regulator is one of the most widely used electronic circuitry in any device. A regulated voltage (without fluctuations & noise levels) is very important for the smooth functioning of many digital electronic devices. A common case is with micro controllers, where a smooth regulated input voltage must be supplied for the micro controller
CRO is a very versatile instrument in laboratory for measurement of voltage, current, frequency and phase angle of any electrical quantity. But before we go ahead with disÂcussion on measurement of electrical quantities with CRO, we should understand some basic oscilloscope patterns. Basic Oscilloscope Patterns Assume that a sinusoidal voltage signal is applied to the
Number of controls are required to be provided on a panel of CRO to facilitate its proper functioning. Intensity control is provided for adjustment of brightness of the spot on the screen. It is accomplished by varying the voltage between the first and second anodes. The horizontal and vertical position controls are provided for moving
Cathode ray tube essentially consists of an electron gun for producing a stream of electrons, focusing and accelerating anodes for producing a narrow and sharply focused electron beam, horizontal and vertical deflection plates for controlling the beam path and an evacuated glass envelope with phosphorescent screen giving bright spot when struck by a high velocity
A CRO (Cathode Ray Oscilloscope) is an electronic instrument used for studying various electrical & electronic parameters and behaviors. CRO is basically an XY (2 dimensional) plotter which can plot an input signal vs another signal or an input signal vs time. A cathode ray oscilloscope is used to study waveforms, transients, time based or
Q-Meter We know that every inductor coil has a certain amount of resistance and the coil should have lowest possible resistance. The ratio of the inductive reactance to the effective resistance of the coil is called the quality factor  or Q-factor of the coil. So Q = XL / R = ωL / R A
Electronic Multimeters It is one of the most versatile general purpose instruments capable of measuring dc and ac voltages as well as current and resistances. The solid-state electronic multimeter (or VOM) generally consists of the following elements. A balanced bridge dc amÂplifier and a PMMC meter. An attenuator in input stage to select the proper
Electronic Galvanometers A vacuum tube or transistor amplifier, followed by a milli-ammeter may be employed as a detector. Some of such devices have arbitrary scale values, sometimes with variable gain, and are designed simply as balance indicators. The sensitivity may be of the order of a microvolt per scale division or better, and the input impedance is
Balanced Bridge Voltmeters Such voltmeters can be used for measurement of both dc and ac voltages and are very popular. These voltmeters are available in both versions, vacuum tube type and transistorized type and are described below: (a) Balanced Bridge Triode VTVM. The circuit diagram of a balanced bridge triode VTVM is shown in figure.
True RMS Reading Voltmeter RMS value of the sinusoidal waveform is measÂured by the average reading voltmeter of which scale is calibrated in terms of rms value. This method is quite simple and less expensive. But sometimes rms value of the non-sinusoidal waveform is required to be measured. For such a measurement a true rms
In electronic ac voltmeÂters input signal is firstly rectified and then supÂplied to the dc amplifier, as shown in figure. Sometimes signal is firstly amplified by ac amplifier and then rectiÂfied before supplying it to dc meter, as shown in figure. In the former case the advantage is of economical amplifiers and the arrangement is usually used
DC Voltmeter Block Diagram DC voltmeter mainly consists of a dc ampliÂfier apart from the attenuator, as shown in figure. DC voltmeters can further be divided into two categories. 1. Direct Coupled Amplifier DC Voltmeter This type of voltmeter is very common because of its low cost. This instrument can be used only to
In all electronic voltmeter circuits the principle involved is that an indication on a permanent magnet moving coil instrument (normally abbreviated as PMMC or D’Arsonval movement) proportional to the input voltage is obtained by means of amplification in one or more stages with a high input impedance. Although electronic instruments are usually more costlier than
VCO (Voltage controlled oscillator) Voltage controlled oscillator is a type of oscillator where the frequency of the output oscillations can be varied by varying the amplitude of an input voltage signal. Voltage controlled oscillators are commonly used in frequency (FM), pulse (PM) modulators and phase locked loops (PLL). Another application of the voltage controlled oscillator
All About Function Generators A function generator is a signal source that has the capability of producing different types of waveforms as its output signal. The most common output waveforms are sine-waves, triangular waves, square waves, and sawtooth waves. The frequencies of such waveforms may be adjusted from a fraction of a hertz to several
A PUT controlled sawtooth generator circuit is shown in figure. When power is first applied, the programmable unijunction transistor (PUT) is off. The capacitor C begins to charge up and the output voltage rises. This continues until the output voltage (which is also the PUT anode voltage) is about 0.7 V above the control input
Sawtooth wave generator. Many people often get confused between sawtooth wave and a triangular wave. Sawtooth waveform is a type of linear non sinusoidal waveform with a triangular shape in which the rise time and fall time are different. A pure triangular waveform is is also linear, non sinusoidal and have a triangular shape but
How to make a Triangular waveform using Schmitt Trigger and Integrator ? Another triangular-waveform generator that needs fewer components is shown in figure. The arrangement consists of a non-inverting Schmitt trigger Ax and an integrator A2. The output of a Schmitt trigger is a rectangular wave that drives an integrator. The output of the integrator
Triangular wave generator using opamp This is an interesting project for newbies. This article is about creating a triangular wave generator using opamp IC. There are many methods for generating triangular waves but here we focus on the method using opamps. This circuit is based on the fact that a square wave on integration gives
Schmitt Trigger or Regenerative Comparator Circuit A Schmitt trigger circuit is also called a regenerative comparator circuit. The circuit is designed with a positive feedback and hence will have a regenerative action which will make the output switch levels. Also, the use of positive voltage feedback instead of a negative feedback, aids the feedback voltage
How to make a Monostable Multi Vibrator using 741 IC ? As already explained , a monostable multivibrator (MMV) has one stable state and one quasi-stable state. The circuit remains in its stable state till an external triggering pulse causes a transition to the quasi-stable state. The circuit comes back to its stable state after
How to make an Astable or Free running Multi vibrator using 741 Op-Amp ? The non-sinusoidal waveform generators are also called relaxation oscillators. The op-amp relaxation oscillator shown in figure is a square wave generator. In general, square waves are relatively easy to produce. Like the UJT relaxation oscillator, the circuit’s frequency of oscillation is dependent on
How to make a Zero Crossing Detector using  311 Op-Amp IC ? A zero-crossing detector using IC 311 (8 pin DIP unit) is illustrated in figure. The positive (above 0 V) going input signal drives the output transistor on, the output going low (- 10 V in this connection). The negative (below 0 V) goÂing
