Electronic Circuits and Diagram-Electronics Projects and Design

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…

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…

How to make a Zero Crossing Detector using 741 IC ? Zero-crossing detector is an applied form of comparator. Either of the op-amp basic comparator circuits discussed can be employed as the zero-crossing detector provided the reference voltage Vref is made zero. Zero-crossing detector using inverting op-amp comparator is depicted in figure. The output voltage waveform shown in figure indicates when and in what direction an input signal vin crosses zero volt. In some applications the input signal may be low frequency one (i.e. input may be a slowly changing waveform). In such a case output voltage vOUT may not switch quickly from…

Most digital systems require some kind of a timing waveform, for instance, a source of trigger pulses is required for all clocked sequential systems. In digital systems, a rectangular waveform is most desirable (unlike analog systems where sinusoidal signals are often used). The generators of rectangular waveforms are referred to as multivibrators. Multivibrators are of three types viz astable (or free-running) multivibrators, monostable multivibrators (or one-shot) and bistable multivibrators (or flip-flops). All these multivibrators have already been discussed. Until a few years ago, multivibrators used to be designed using discrete devices, such as vacuum triodes, bipolar junction transistors (BJTs), field-effect…

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…

Design for determining the Free running frequency,Lock range and Capture range of a PLL In the earlier post about Phase Locked Loop IC we had discussed about the free-running frequency (fOUT), lock range (fL) and capture range (fc) equations. Here let us discuss about the appropriate values that can be given for fOUT, fL, and fc. Given below is the circuit of an NE/SE 565 IC or the PLL IC. We assume values for each parameter. +V = 12 Volt -V = -12 Volt R1 = 15 Kilo Ohms C1 = 0.01 Micro Farads C2 = 10 Micro Farads Free-running…

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…

MOS (Metal Oxide Semiconductor)-IC’s As already mentioned in previous blog posts, ICs based upon the active devices are of two types viz. bipolar ICs using bipolar active devices like BJT and unipolar ICs using unipolar active devices such as FET. MOS ICs based on MOSFET structure are widely used in many applications especially in the digital field. This is because of its following advantages over bipolar ICs. 1. Reduction in Size. The MOS IC typically occupies only 5% of the surface required by an expitaxial double-diffused transistor in a conventional IC. Also, a MOS resistor occupies less than 1% of the area of…

How to make an integrated transistor amplifier ? We are now in a position to illustrate how a complete tran­sistor amplifier circuit including bias resistors can be formed on a silicon wafer using the masking and photolithographic processes, described earlier. The difference now is that the masking pattern must be layed out to include the appropri­ate interconnections as well. Appearing in figures is the complete IC layout of the transistor amplifier circuit shown in figure. The five circuit elements—one capacitor, three resistors, and one transistor—and all the interconnections are produced by the same masking, etching, and diffusion process-. In an…

Types of IC Packages For the protection of ICs from external environment and to provide mechanical protection and terminals for electrical connections, various types of packages are used. Several standard packages in general use are shown in figure. The metal can type of container provides electromagnetic shielding for the IC chip which cannot be provided by plastic or ceramic packages. The plastic dual-in-line package is much cheaper than other types of packages and is widely employed for general industrial and consumer applications where high temperatures are not met with. Ceramic or metal contain­ers are used where ICs are subjected to…