28123 Parallax Inc, 28123 Datasheet - Page 46

• Manufacturer Part Number: 28123
• Description: TEXT WHAT'S A MICROCONTROLLER
• Manufacturer: Parallax Inc
• Type: Programmingr

Specifications of 28123

• Style: Book
• Title: What's a Microcontroller?
• Contents: Whats a Microcontroller? Text
• Product: Microcontroller Accessories
• Core Processor: PIC16C57c
• Flash: 128 Bytes
• Operating Supply Voltage: 9 V
• Board Size: 31 mm x 16 mm
• Lead Free Status / RoHS Status: Not applicable / Not applicable

Chapter #2: Lights On – Lights Off
INDICATOR LIGHTS
Indicator lights are so common that most people tend not to give them much thought.
Figure 2-1 shows three indicator lights on a laser printer. Depending on which light is
on, the person using the printer knows if it is running properly or needs attention. Here
are just a few examples of devices with indicator lights: car stereos, televisions, VCRs,
disk drives, printers, and alarm system control panels.
Turning an indicator light on and off is a simple matter of connecting and disconnecting
it from a power source. In some cases, the indicator light is connected directly to the
battery or power supply, like the power indicator light on the Board of Education. Other
indicator lights are switched on and off by a microcontroller inside the device. These are
usually status indicator lights that tell you what the device is up to.
MAKING A LIGHT EMITTING DIODE (LED) EMIT LIGHT
Most of the indicator lights you see on devices are called light emitting diodes. You will
often see a light emitting diode referred to in books and circuit diagrams by the letters
LED. The name is usually pronounced as three letters: “L-E-D”. You can build an LED
circuit and connect power to it, and the LED emits light. You can disconnect the power
from an LED circuit, and the LED stops emitting light.
Figure 2-1
Indicator
Lights