Electricidade e electrónica en inglés para a sección bilingüe de tecnoloxía de 3º ESO

1. Electricity and Electronic Lesson 2, Technology Sección bilingüe Xosé M. Rodríguez

6. Electronic devices http://www.bbc.co.uk/schools/gcsebitesize/design/electronics/materialscomponentsrev1.shtml

7. Resistors A resistor is a two-terminal electronic component designed to oppose an electric current by producing a voltage drop between its terminals in proportion to the current. Color code of resistors

8. Variable resistors A potentiometer is a three-terminal resistor with a sliding contact to change the value. Potenciometer . LDR (Light Dependent Resistor) Is a resistor whose resistance decreases with increasing incident light intensity Temperature Dependent Resistors NTC PTC Is a resistor whose resistance increases with increasing temperature. Is a resistor whose resistance decreases with increasing temperature.

10. LED A LED is a semiconductor diode that emits light when an electric current is applied in the forward direction of the device.

12. Transistors are easily damaged, so it is important not to mix up the three leads. To help identify the leads some transistors have a dot near the collector, and/or a tab near the emitter. Each type of transistor is identified by a code printed on the side and then you can learn about it in the datasheet .

14. Some transistors

15. Darlington pairs Some transistors can take a very low current flowing in the base and amplify it to give a much higher current in the collector (called gain ). Other transistors can output a large current at the collector - but without very much gain. Single transistors cannot have both high gain and high collector current. To overcome this problem, a high-gain transistor is paired up with a high-current transistor in what is called a Darlington pair . The combined transistors allows both a higher gain and a larger amount of current to flow than would be possible with a single transistor . Darlington pairs are often used to drive motors.

18. Some capacitors

22. Very simple circuit Light sensor

23. Vin Potential divider

24. I Base Cutoff : I BASE = 0 A => I Collector = 0 A Saturation : I BASE is high => I Collector = I CSAT I collector BC548 I CSAT = 10 mA Look for this data in the web (datasheet) I emitter

26. Humidity sensor