28128 Parallax Inc, 28128 Datasheet - Page 18

• Manufacturer Part Number: 28128
• Description: KIT BASIC ANALOG/DIGI PARTS ONLY
• Manufacturer: Parallax Inc

Specifications of 28128

• Accessory Type: ADC, DAC
• Product: Microcontroller Accessories
• For Use With/related Products: BASIC Stamp® 2 and Board of Education
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The potentiometer is what makes the analog output. The op-amp is wired to function as a
voltage follower. The voltage follower drives the analog LED output. Then there's a
separate circuit that uses a BASIC Stamp I/O pin to drive an LED.
Figure 1-8 shows a breadboard example of the schematic from Figure 1-7. For extra tips
on building circuits on the breadboard, consult What’s a Microcontroller?
P12
P7
output from
Pot with
terminal
Vdd
analog
Vss
wiper
100k
Pot
Ω
follower circuit
Op-Amp
voltage
Vdd
Vss
A
LM358
Analog LED
LED
output
Vss
470 Ω
output.
Binary
LED
Vss
LED
470 Ω
Figure 1-7
Circuit Schematic.
Remember to treat
this schematic like
a list of
connections for
building your
circuit.
Although this circuit
only has a few
parts, it actually
has 4 separate sub
circuits, and each
has a different
function as shown