28122 Parallax Inc, 28122 Datasheet - Page 149

• Manufacturer Part Number: 28122
• Description: KIT WHAT'S A MICRO:PARTS ONLY
• Manufacturer: Parallax Inc

Specifications of 28122

• Accessory Type: Parts Kit
• Product: Microcontroller Accessories
• Core Processor: PIC16C57c
• Flash: 128 Bytes
• Operating Supply Voltage: 9 V
• Board Size: 31 mm x 16 mm
• For Use With/related Products: Board of Education Full Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ACTIVITY #1: BUILDING AND TESTING THE POTENTIOMETER CIRCUIT
Placing different size resistors in series with an LED causes different amounts of current
to flow through the circuit. Large resistance in the LED circuit causes small amounts of
current to flow through the circuit, and the LED glows dimly. Small resistances in the
LED circuit causes more current to flow through the circuit, and the LED glows more
brightly. By connecting the W and A terminals of the potentiometer, in series with an
LED circuit, you can use it to adjust the resistance in the circuit. This in turn adjusts the
brightness of the LED. In this activity, you will use the potentiometer as a variable
resistor and use it to change the brightness of the LED.
Dial Circuit Parts
(1) Potentiometer – 10 kΩ
(1) Resistor – 220 Ω (red-red-brown)
(1) LED – any color
(1) Jumper wire
Building the Potentiometer Test Circuit
Figure 5-5 shows a circuit that can be used for adjusting the LED’s brightness with a
potentiometer.
√
Build the circuit shown in Figure 5-5.
Tip: Use a needle-nose pliers to straighten the kinks out of the potentiometer’s legs before
plugging the device into the breadboard. When the potentiometer’s legs are straight, they
maintain better contact with the breadboard sockets.