Ramsey Electronics PM10DC, Manual

Page: 17 / 40

PM10DC
y
17
ˆ 20. Install C16, a 10pF ceramic capacitor (Marked 10 or 10K).
ˆ 21. Install C3, a 0.01uF ceramic capacitor (Marked 103).
ˆ 22. Install L1, a 3.9uH inductor (orange-white-gold). This inductor keeps
any noise on the power supply out of the side of the circuit which contains
the AD8307. Any noise present on the ICs is detected and would give us
incorrect readings with low level signals if it were not blocked by the
inductor.
ˆ 23. Install C19, a 10uF electrolytic capacitor. Again pay attention to
polarity.
ˆ 24. Install U1, the LMC662 Dual Rail to Rail opamp. Make sure to align
the dimple or notch with the dimple as indicated on the parts layout
diagram. This indicates pin one of the device. Solder all 8 pins.
ˆ
25. Install U2, the ADS7841PBN 12-Bit analog to digital converter. Make
absolutely sure you align pin one as shown! Solder all 16 pins.
ˆ 26. Install the 20-Pin socket in place of U4; this will allow you to easily
replace U4 in case of any available code updates.
ˆ 27. Install U4 in the previously installed socket. This is the
MC68HRC908JK3 (it may have a silver sticker). This is the micro-
controller, and therefore contains all of the intelligence of the kit. Make
sure pin 1 is aligned properly and that all 20 pins are lined up before
seating the IC into place.
ˆ 28. Install C15, a 0.01uF ceramic capacitor (Marked 103).
ˆ 29. Install VR1, the 78L05 voltage regulator. This part has the job of
making the supply voltage “flat” at 5.0V output with a number of varying
inputs.
ˆ 30. Install C23, a 10uF electrolytic capacitor. Again check polarity.
ˆ 31. Install D1, a 1N4002 type rectifier diode. This diode has the job of
converting AC power to DC power from your power supply and also
preventing you from accidentally applying the wrong polarity to the power
supply. This gives us pulsed DC, which C24 will smooth out for us.
ˆ
32. Install C24, the 1000uF electrolytic capacitor. Pay very close attention
to polarity, since putting this big capacitor in backwards can be a large
problem.
Now we are going to install our surface mount components. Since it is really
easy to lose them we will want to put them in a small container or set of
containers like a cardboard egg carton. Plastic egg cartons will have too much
static since they are Styrofoam so don’t use those. Sort out all of your
components and note that we give you extra, because we know a few will fly