122-28176 Parallax Inc, 122-28176 Datasheet - Page 60

• Manufacturer Part Number: 122-28176
• Description: GUIDE STUDENT PROCESS CONTROL
• Manufacturer: Parallax Inc

Specifications of 122-28176

• Accessory Type: Manual
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

How much voltage is dropped across R
The total voltage of the series circuit in Figure 3-3b is:
Kirchoff's Voltage Law is upheld in that the sum of the voltages equals the supply
voltage.
The voltage divider formula may also be used to find V
For Figure 3-3c, what is V
equal; therefore, the voltage drops must be equal to one-half of the supply voltage.
This voltage is measured by the analog to digital converter and used as input to P8.
When the voltage divider produces a voltage at or above 1.45 V, P8 senses a HIGH.
When below 1.45 V, P8 senses a LOW.
The analog to digital converter is measuring the voltage, 0 to 5 V, and the BASIC Stamp
is reading the ADC using the
for a digital value from 0 to 255.
The brackets instruct StampPlot to perform math on the data string prior to plotting it.
For a digital value of 128, the string would be
StampPlot will perform the math, plot and display 128 * 0.0196 or 2.51, representing the
voltage. Deeper discussions on ADCs and scaling data are in later chapters.
√
V
V
V
V
Calculate V
DEBUG "[ADC_DataIn,*,.0196]"
255 x .0196 = 4.998 V
R2
R1
R1
R2
=Vdd(R
= I(R
= (IR
+ V
R2
R2
R1
= 1 V + 4 V = 5 V
)= (0.5 mA)(8 kΩ) = 4 V
R2
R2
= (0.5 mA)(2 kΩ) ) = 1 V
/R
for Figure 3-3d.
1
+ R
R2
? Without using any math, we can see the resistances are
2
SHIFTIN
)) = 5 V(8 kΩ/(8 kΩ +10 kΩ) = 5 V(8 kΩ/10 kΩ) =4 V
DEBUG
1
in Figure 3-3b?
instruction. The voltage is represented by 8-bits
sends this value to StampPlot in the form of:
[128,*,.0196]
R2
:
.