DATASHEET and Circuit Diagram

The following semiconductor article reviews how to design RF Circuits – Oscillators which is concentrated on a worked example of a Clapp oscillator, using a varactor tuned ceramic coaxial resonator for voltage control of the output frequency. This circuit used to be applied at Plextek in Satellite Digital Audio Broadcasting circuits, and in telemetry links for Formula One racing cars.

What you will see in the depth of the article are sections such as General Equivalent Circuits for RF Oscillators, Schematic for Small-Signal Oscillator Design, Small-Signal Negative Resistance Simulation, Schematic for Large-Signal Oscillator Design, Large-Signal Oscillator Phase Noise Simulation and more.

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The diagram below appears Miniatur Alarm Generator Circuit for Laptop Protector. It such a home made tilt switch fixed inside the laptop case in order to protect laptop against theft since it will sounds loud when someone tries to take the laptop.

This device is powered by a 12V battery used in remote control devices. The components of this miniature alarm generator are readily available to be assembled on general PCB. It uses such IC TLO71 (IC1) for the voltage comparator, and IC CD4538 (IC2) for a monostable multivibrator.

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A circuit diagram for driving a plasma-type display using ICL7135 is shown in the following schematic. This application is one of the wide versatility variety of this integrating Analog to Digital Converter device. The integrating converter characteristics have made it the natural choice for panel meters and digital voltmeter applications.

The schematic outlines the high voltage anode driver buffer, the 3 AND gates for interdigit blanking of multiple-digit display elements, and 2.5kOhms and 3kOhms resistors that set the current levels in the display.

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The following injector driver circuit is designed to work with most Engine Control Module (ECM) as well. It is used to drive the other two injectors in a four injector throttle body in which ECM drives two of them and this device uses one of the injector drive lines as the trigger signal to drive the other two.

This Injector Driver Schematic Diagram uses two injector driver chip LM1949 that controlled voltage drops in the ECM, two TIP122 big transistors (Q1 and Q3), two NPN transistors (Q2 and Q4) to invert the signal from the op-amp and limit the voltage swing to +5V to protect the input on the LM1949.

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This document may help you understanding the bootstrap circuitry since it contains such information related. A bootstrap circuit is an arrangement of components used to boost the input impedance of a circuit by using a small amount of positive feedback, usually over two stages (wikipedia.org).

What you will read in this document are sections describe Operation Of The Bootstrap Circuit, Influencing Factors Affecting The Bootstrap Supply, Calculating The Bootstrap Capacitor Value, How to Select The Bootstrap Diode, and Recommended Layout of the Bootstrap Components (Layout Considerations).

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This digital-to-analog converter (DAC) integrated circuit is designed for lowest noise performance, both radiated and conducted noise. A recommended connection diagram for the ADV7123 is shown in the following schematic diagram.

According to the ADV7123 datasheet, this device consists of three high speed, 10-bit, video DACs with complementary outputs, a standard TTL input interface, and a high impedance, analog output current source. It used to be applied in digital video systems, image processing, digital radio modulation, color graphics and more.

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The following DC power supply (PSU) is designed for the ham radio transceivers. It such a regulated DC power supply with short circuit safe and current limiter. This PSU can deliver 20Amps at 13.8V using a simple 12V regulator of the IC7812.

This power supply circuit was built with semiconductors as follows: transistors (BC 557B, BD330, 2N5683, BC547), 7812 IC Regulator, various resistors, capacitors (40.000uF, 33nF, 1uF Tantal, 100nF) and etc.

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Oxygen (O2) sensors are used to sense the amount of oxygen in the exhaust gases. The following circuit uses two LM3914s Dot/Bar Display Driver IC for the LED display. This O2 sensor circuit will be used as air fuel mixture meter of cars.

This sensor operates at 5V regular supply, uses 1/4 Watt 1K resistors, 10V 2.2 or 4.7 uF filter capacitor and 0.95V potentiometer on pin 6 of LM3914 which will cause the last LED to turn on when the input from the sensor exceeds 0.95V. To prevent over voltage of the battery, it uses regulator which also has an internal thermal sensing circuit that limits the current output to avoid damaging the regulator.

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The following semiconductor article provide you with information about basic and simple power supply regulators, a few basic circuit in understanding on how some of the more sophisticated power supplies circuit operated such as the 7800/7900 series, and the LM723.

You will be taken into explanation about why using a regulator in a power supply circuitry, the principle of short-circuit device for maintaining circuit continuity, switching type regulators and electromechanical regulators, and explanation about several simple regulator circuit such basic shunt regulator, simple regulator for higher current, simple adjustable regulator, feedback regulator with single transistor error amplifier, feedback regulator with current limiting (click to enlarge), the use of op amp as error amplifier, transistor current regulator, the use of LM7805 as current regulator, and the use of LM723C regulator with bypass resistor.

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The basic structure to create a current boosting switch using an NPN transistor is shown in this circuit diagram. Current boosters are needed to step up the current to an adequate level needed by the high current and high voltage circuits.

The following article will demonstrate ways to uses transistors as current boosting switches. You will find informations related to microprocessors and IC’s with the transistors, saturating the right transistor (step-by-step process to choosing the right transistor), and simulation examples. Thus, this article offers tools and techniques to boost the current while maintaining the functionality of circuit system.

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