70 Circuitos eleonicos

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See TALKING ELECTRONICS WEBSITE email Colin Mitchell: talking@tpg.com.au

Save 70 Interesting Circuits as: zip (1.9MB) or .doc (1.7MB) or .pdf (1.15MB) (14-9-2010)
For our other free eBooks: 50 - 555 Circuits 1 - 100 Transistor Circuits 101 - 200 Transistor Circuits 100 IC Circuits For a list of every electronic symbol, see: Circuit Symbols.

For more articles and projects to suit thehobbyist: see TALKING ELECTRONICS WEBSITE

INTRODUCTION
This e-book covers a number of interesting circuits.
They have been presented for a reason. The original circuits come from an Indian Electronics Magazine and most of them had faults. Either they were over-designed, poorly designed or contained a fault. In the process of bringing these faults and corrections to you, we have created this eBookof 70 Interesting Circuits. You can lean a lot from other peoples mistakes. Not only will you remember not to make the same mistake but the corrections and improvements generally require less components. The art of designing a circuit is to make it as simple as possible and use the least number of components. But before you put a design into production, get someone else to look at it. Another "setof eyes" will see things differently and maybe simplify or improve the design. We have already presented a set of pages called "Spot The Mistake," showing dozens of faulty circuits and how to check and test things before releasing them. It is surprising that a magazine with a readership of over 1,000,000 could publish items with glaring faults. The faulty projects in this collection have arevised circuit included in the article and you can compare the two designs. It only takes a minute to see a circuit will not work and a few more minutes to create a improved design. This is what we are teaching in this section . . . how to look at a circuit with a "critical eye" then design an improvement. This is called REVERSE ENGINEERING and involves the highest level of technical skill. But it isalso the fastest way to test a persons skill and the fastest way to learn. That's why I consider it to be the most important approach to learning. Colin Mitchell TALKING ELECTRONICS. talking@tpg.com.au

CONTENTS
AC Detector Auto Cutout Battery Monitor Capacitance Beeper Constant Current Source Door Watcher Electronic Siren 555 Schmitt 10 Output LED Sequencer 12v Lamp Dimmer 16 LED Night RiderUltrasonic Remote Control

Emergency Light Increasing the input Impedance Light Controlled Lamp Lightening Detector Moving LEDs
to Index

10 OUTPUT LED SEQUENCER

Here is 10 output LED sequencer. After the last LED is illuminated, the circuit is reset. This circuit is build around readily a low cost components - a 555 and decade counter CD4O1 7. The timer IC NE555 is wired as an astablemultivibrator that produces 6Hz clock at its output pin 3. The 4017 is a CMOS decade counter with 10 outputs. Inputs include a CLOCK (Pi RESET (Pin 15), and a CLOCK INHIBIT (Pin 13). The clock input connects to a Schmitt trigger for pulse shaping and allo clock rise and fall times (not needed in our case). The counter advances one output at the rising edge of the clock signal if the CLOCK INHIBIT lineis low. A high RESET s resets the counter to the zero output. The circuit may be configured for counts less than 10 by connecting RESET to an o (one after the desired count). Thus, a five stage sequencer can be made by connecting pin 15 to pin 1. A CARRY-OUT si 12) can be used to clock subsequent stages in a multi-device counting chain. The output from 1C2 pin 3 is connected to clock pin (pin 14)of the IC3 for sequencing operations. NPN transistors Q1- Q used to increase the output current for the LEDs which is set by the common 150 ohm resistor. In the circuit, only one of t outputs is HIGH at any one time and the output advances by one count with every clock pulse.

But the circuit above is poorly designed. It does not need the voltage regulator as both chips can work up to 15v....
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