PLL Application – Frequency Demodulation Using NE-SE 565 IC Frequency demodulation or detection can be obtained directly by using the PLL circuit. When the centre frequency of the PLL is selected or designed at the FM carrier frequency, the filtered or output voltage in the circuit shown in figure, is obviously the desired demodulated voltage, […]
PLL Applications 1. Frequency Multiplication or Frequency Synthesis The block diagram of a frequency muliplier (or synthesizer) is shown in figure. In this circuit, a frequency divider is inserted between the output of the VCO and the phase comparator (PC) so that the loop signal to the PC is at frequency fOUT while the output
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.
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
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
Phase Locked Loops (PLL) Introduction to PLL The concept of Phase Locked Loops (PLL) first emerged in the early 1930’s.But the technology was not developed as it now, the cost factor for developing this technology was very high. Since the advancement in the field of integrated circuits, PLL has become one of the main building
Introduction to Operational Amplifiers In this post, the basics of an operational amplifier (generally abbreviated as op-amp) will be analysed along with its block diagram, basic structure, symbol, types and a detailed explanation of the typical op-amp. What is an operational amplifier (op-amp)? An op-amp is a multi-stage , direct coupled, high gain negative feedback
F to V Converter Circuit using LM555 Timer Description. Here is a very simple circuit diagram of a frequency to voltage (F to V) converter. Such a circuit finds numerous applications in projects like digital frequency meters, tachometers etc. The circuit is mainly based on a LM555 timer IC. The IC is wired in mono
Description. Here is the circuit diagram of a fully transistorized inverter that can drive up to 60W loads. Transistors Q1 and Q2 forms a 50Hz astable multivibrator. The output from the collector of Q2 is connected to the input of the Darlington pair formed by Q3 and Q4.Similarly the output of Q1 is coupled to
Programmable UJT (PUT). Programmable unijunction transistor or PUT is a close relative of the thyristor family. Its has a four layered construction just like the thyristors and have three terminals named anode(A), cathode(K) and gate(G) again like the thyristors. Yet some authors call it a programmable UJT just because its characteristics and parameters have much
UJT relaxation oscillator UJT relaxation oscillator is a type of RC ( resistor-capacitor) oscillator where the active element is a UJT (uni-junction transistor). UJT is an excellent switch with switching times in the order of nano seconds. It has a negative resistance region in the characteristics and can be easily employed in relaxation oscillators. The
Description. This circuit diagram shows you how to make a 5V to 12V variable DC power supply from a fixed 5V regulator IC 7805. This is attained by adding two resistors R1 and R2 as shown in figure. When the resistors R1 and R2 are added the equation for the output voltage of 7805 becomesÂ
How to trigger an SCR using UJT ? One common application of the uni junction transistor is the triggering of the other devices such as the SCR, triac etc. The basic elements of such a triggering circuit are shown in figure. The resistor RE is chosen so that the load line determined by RE passes
UJT Characteristics The static emitter charÂacteristic (a curve showing the relation between emitter voltage VE and emitter current IE) of a UJT at a given inter base voltage VBB is shown in figure. Â From figure it is noted that for emitter potentials to the left of peak point, emitter current IE never exceeds IEo .
Description. This is the circuit diagram of a very sensitive electromagnetic field sensor which can sense electromagnetic field from 40Hz to 140Hz. The low noise opamp LF351 and associated components forms the pick-up section. 1uH coil L1 is used for sensing the field and the IC1 performs the necessary amplification. If the picked electromagnetic field
In this article, we learn about UJT (Uni Junction Transistor) in detail. We cover a lot about UJT like – what is basically a UJT, how they differ from other transistor models, how to construct a UJT, operation & working of a UJT, how to build applications of UJT and so much more. Lets dive
Light activated SCR (LASCR) or a Photo SCR Â is just an ordinary SCR except that it can also be light triggered. Most LASCRs also have a gate terminal for being triggered by an elecÂtrical pulse just as a conventional SCR. The basic construction of an LASCR is shown in figure. The schematic symbols most commonly
A simple sawtooth generator using a GTO and a Zener diode is shown in figure. When the supply is switched on, the GTO will turn on, resulting in the short-circuit equivalent from anode to cathode. As a consequence the capacitor C will begin to charge toward the supply voltage, as illustrated in figure. As the
Description. Here is the circuit diagram of a simple and low cost AM radio. The working of this radio circuit is straight forward. Inductor L1 and capacitor C1 forms the necessary tank circuit. Diode D1 performs the job of de-modulation. Transistor T1 is wired as a preamplifier whose output is further amplified by the IC
Gate turn-off switch (GTO) is, like an SCR, is a four layer, three junction semiconductor device with three external terminals, namely, the anode, the cathode and the gate, as illustrated in figure. The basic construction, schematic symbol of a GTO are shown is figures  respectively.  Although the graphic symbol is different from either the SCR
The diac and the silicon bilateral switch are grouped as bilateral or bidirectional devices because they can breakover in either direction. There are also breakover devices which breakover in only one direction; they fall in the category of unilateral or unidirectional breakover devices. Although unilateral breakover devices are more frequently employed in SCR triggering, they
Silicon bilateral switch (SBS) is another breakover device which is capable of triggering triacs, and it is popular in low-voltage trigger control circuits. They have breakover voltages lower than those for diacs, ± 8 V being the most popular rating. V-I characteristic curve of an SBS is similar to that of the diac, but it
The four-layer diode, also called the Shockley diode after its inventor William Shockley, is essentially a low-current SCR without a gate. It is classified as a diode because it has only two external terminals through anode and cathode. Because of its four doped regions it is often called a P-N-P-N diode. You can find more
Silicon controlled switch (SCS), like the SCR, is a unilateral, four layer three junction P-N-P-N silicon device with four electrodes namely cathode C, cathode gate Gx, anode gate G2 and the anode A, as shown in figure. Infact, the SCS is a low power device compared with the SCR. It handles currents in milli amperes
As mentioned earlier, low-current drop out is the normal way in which the SCR is turned off. Gate-controlled switch is designed for easy opening with a reverse-biased trigger. A gate controlled switch (GCS) is closed by a positive trigger and opened by a negative trigger (or by low-current drop out). Gate-controlled switch circuit is shown
