Micro Electronics

Microelectronics

Through the 1980's and into the 1990's, the variety of products being built with electronic components increased, and the use of electronic control devices led to greater automation. Microelectronics led to the development of new technologies, such as digital audio recording; to the introduction of new products, such as personal computers; and to the reduction in the size of portable telephones and many other electronic products

Voltage Regulation

A voltage regulator is used to help keep the output voltage at a desired level. A simple type of voltage regulator consists of a resistor in series with and a zener diode in parallel with the output of the power supply. The diode is used with a reverse bias above its breakdown voltage so that it will conduct a reverse current. In this mode of operation, a very small change in voltage across the diode causes a very large change in the current through the diode. Should the voltage at the input to the regulator increase, the diode conducts more current and the current  through the resistor increases. This action increases the voltage drop across the resistor in such a way that the voltage at the output remains the same.

Power Supplies

A device that supplies electricity to an electric circuit is called a power supply. Portable electronic devices are typically powered by batteries, which provide direct current. Household current is alternating current, and the power supply of electronic equipment designed to operate on household current must convert it into direct current. In addition, the power supply provides the current at one or more specific voltages

Filtering

The output signal produced by the full-wave rectifier is a DC voltage, but it pulsates. To be useful, this signal must be smoothed out to produce a constant voltage at the output. A simple circuit for filtering the signal is one in which a capacitor is in parallel with the output. With this arrangement, the capacitor becomes charged as the voltage of the signal produced by the rectifier increases.