130-28176 Parallax Inc, 130-28176 Datasheet - Page 66

• Manufacturer Part Number: 130-28176
• Description: KIT PARTS PROCESS CONTROL
• Manufacturer: Parallax Inc

Specifications of 130-28176

• Accessory Type: Education Kit
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Board of Education Full Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

The pull-down resistor R
is not pressed, keeping it LOW. When the button is pressed, current flows through R
allowing a HIGH to be sensed on P8. The pull-down resistor should be sized to prevent
excessive current flow when the button is pressed.
Typical values for resistors used for this purpose are 1 kΩ, 10 kΩ or even 100 kΩ. A
minimum amount of current is required, typically several microamps.
I
R5
=V
R5
/R
5
= 5 V/10 kΩ = 0.5 mA
5
is used to force the input to a low voltage when the pushbutton
Figure 3-8
Active-High
Pushbutton with Pull-
Down Resistor
5
,