Archive for the ‘Integrated Circuits’ Category

Photonic Integrated Circuit

Photonic Integrated Circuit Technology Photonic Integrated Circuit (also known as PIC), is a complex integrated circuit which incorporates a lot of optical devices to form a single photonic circuit. The main difference between a PIC and an Electronic IC is that PIC is analogous to an Electronic Integrated Circuit.  Many optical devices like optical amplifiers, multiplexers, de-multiplexers, optical lasers, attenuators and also detectors are integrated on to a Photonic Integrated Circuit. For a large-scale operation of such a device thousands of optical devices will be integrated on to the device. In a PIC, the signals are sent by superimposing them…

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Schmitt Trigger using Op-Amp

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 to the input voltage, instead of opposing it. The use of a regenerative circuit is to remove the difficulties in a zero-crossing detector circuit due to low frequency signals and input noise voltages. Shown below is the circuit diagram of a Schmitt trigger. It is…

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Pulse Generator using Op-Amp

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 a time period T. Thus it generates a single output pulse in response to an input pulse and is referred to as a one-shot or single shot. Monostable multivibrator circuit illustrated in figure  is obtained by modifying the astable multivibrator circuit  by connecting a diode…

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Square Wave Generator using Op-Amp

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 the charge and discharge of a capacitor C through feedback resistor R,. The “heart” of the oscillator is an inverting op-amp comparator The compa­rator uses positive feedback that increases the gain of the amplifier. In a comparator circuit this offer two advantages. First, the high…

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Zero Crossing Detector using IC 311

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) go­ing input drives the output transistor off, the output going high (+ 10 V in this connection). The output is thus an indication of whether the input is above or below 0 V. When the input is any positive voltage (above 0 V), the output is…

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Zero Crossing Detector

In this article, we discuss Zero Crossing Detector in detail with two different circuits. In the initial paragraphs of the tutorial, you will learn zero crossing detector using op amp designed using the popular 741 IC. We have a neat draw circuit diagram of zero crossing detector and we have explained its working principle and theory behind the scene in easy to understand words. Towards the middle of this tutorial, you will learn about 2 applications of zero crossing detector – which are time marker generator and phasemeter. Towards the end of article, we have drawn another circuit diagram of…

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Op-Amp Comparator

In this post we will be discussing about the op-amp as a comparator.We have already discussed other applications of the op-amp in rectangular wave form generator circuits like astable (or free-running) multivibrators, monostable multivibrators (or one-shot) and bistable multivibrators (or flip-flops). To get a better understanding of operational amplifiers click here:- Operational Amplifiers (Op-amp)  Op-amp Comparator A comparator finds its importance in circuits where two voltage signals are to be compared and to be distinguished on which is stronger. A comparator is also an important circuit in the design of non-sinusoidal waveform generators as relaxation oscillators. In an op-amp with an open loop…

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PLL Operation

How a PLL works ? Consider VCO operating without input signal at free-running frequency fr and input signal of frequency fIN increasing from zero is applied to the PC. If the input frequency is less than fIN1, then the error voltage Ve is zero as illustrated in figure and VCO operates at a frequency fr. When the input signal frequency fIN reaches a frequency fin1 (the lower edge of the capture range), then the output or error voltage Ve jumps from zero to some negative voltage with beat notes of frequency (difference between input signal frequency and actual VCO output…

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Phase Locked Loop IC’s

MONOLITHIC PHASE-LOCKED LOOP (PLL) ICS Although the evolution of the PLL began in the early 1930s but its cost outweighted its advantage in the beginning. Today the PLL is even available as a single package, typical examples of which are the Signetic’s SE/NE series such as 560, 561, 562, 564, 565 and 567. They only differ in operating frequency range, power requirements, and frequency and bandwidth (BW) adjustment ranges. SE/NE 565 is the most widely employed IC of the series. The device is available as a 14-pin DIP package  and as a 10-pin metal can package. Its important electrical characteristics…

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PLL Operating Principle

Operating principle of Phase Locked Loops The block diagram showing operating principle of PLLis given in figure. As illustrated in this fig, the PLL consists of a phase detector, a low-pass filter and a voltage controlled oscillator. YOU MAY ALSO REFER: PHASE LOCKED LOOP IC’s, DESIGN A PLL, PLL OPERATION, and PLL FM DEMODUATOR CIRCUIT Phase Detector A phase detector is basically a comparator that compares the input frequency fin with feedback frequency fout. The phase detector receives two digital signals, one from the input, the other feedback from the output. The loop is locked when these two signals are of the same frequency…

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