Gas station without pumps

Parts orders for Applied Circuits W13

On this page I will record the purchases I make for the Applied Circuits course, along with any notes about pricing. In some cases I’m combining orders with personal orders, to reduce shipping charges. In those cases I’ll prorate the shipping based on the dollar amounts of the personal and student items.  Combining orders like this should reduce the amount the students pay for shipping, as the shipping cost has a large constant amount per order.

ITEAD purchase 2012 Dec 16:

Item Sku Qty Subtotal
Electrolytic Capacitor (1UF-470UF) 12 in 1 Package IM120721003 3 $18.00
Capacitor (1pF-0.1uF) 25 in 1 Package IM120721001 20 $96.00
Small Batch 2Layer PCB 5cm x 5cm Max
PCB Qty
50pcs
PCB Color
Green
PCB Thickness
1.6mm
Surface Finish
HASL
E-test
100% e-test
IM120418013 1 $45.00
2Layer Green PCB 5cm x 5cm Max
PCB Thickness
1.6mm
Surface Finish
HASL
E-test
100% e-test
Open Source And Get 2 More Additional Boards
No
IM120418001 3 $29.70
2.54mm 40Pin Male Lengthen Header (5 Psc) IM120531015 4 $6.00
PERSONAL ITEM XXXX 1 $35.00
Subtotal $229.70
Shipping & Handling $45.50
Grand Total $275.20

One of the 3 sets of electrolytic capacitors is for my use at home as is one of the sets of double-ended male headers. I find the double-ended headers very useful for adding scope probe points to breadboards or making Arduino pins accessible. I’ll probably use the capacitors and headers for development of the course, but I’ll be keeping them for myself, so will pay for them myself. Overall, the personal purchases on this order are $42.50, plus $8.42 for pro-rated shipping = $50.92.

One of the 10-piece PC board orders is for the pressure sensor boards, which should be reimbursed by the University. That is $9.90 plus $1.96 for prorated shipping = $11.86.  I’ll be adding two more from a previous order that I paid for myself, so that should be $11.88+$2.35=$14.23 for the PC boards.

The approximate price per student for parts on this order is ($275.20 – $11.86 -$50.92)/20= $10.62, but I’ll be a bit more careful than that, and figure the price per student more exactly based on the parts we’ll actually pack into their kits, adding 19.8% for the prorated shipping:

Item Qty Subtotal
electrolytic capacitors 12 60¢
ceramic capacitors 250 $4.80
hysteresis oscillator board 1 45.5¢
instrumentation amp protoboard 2 $1.80
double-ended male headers 20 15¢
Subtotal $7.81
Prorated shipping $1.55
Total price per student $9.35

Note that I’ll be absorbing any extra costs for extra parts (like ordering 50 instrumentation-amp protoboards instead of 40), as well as the prorated shipping costs for those extra parts.  I chose the UPS shipping option rather than the slightly cheaper airmail, because it is supposedly much faster and more reliable (and my experience with airmail from ITEAD in Hong Kong does indicate that it is quite slow).  With the current class size of 18, they’ll be paying $168.30, the University $11.86, and the remaining $95.04 I’ll pay.  I will have a few instrumentation amp proto boards that I can sell to the students if they need spares, but I don’t think they’ll need them.


Utopia tools 2012 Dec 17

screwdriver set (should handle tiny screw terminals, trim pots,  and alligator clips): http://www.utopiatools.com/Econo-Mini-Screwdriver-Set.html

SKU Product Item price Quantity Total
U16SCREC Econo Mini Screwdriver Set $1.20 20 $24.00
Subtotal: $24.00
Shipping cost: $8.05
CA Tax 7.75%: $1.86
Total: $33.91

This adds $1.70 per student, bringing the total so far to $11.05/student.


FusionBeads 2012 Dec 17

Image
Name/Code
Product Name
Options
Price
Qty
Total
Image FW0113 24 Gauge Fine Silver Wire
$29.95 1 $29.95
10% Discount 10% Discount (holly10)
(10.00)% 1 ($3.00)
Tax 0.00
Total $26.95

Students will get 1′ of the fine silver wire, and the total order is 0.5oz (about 24′), so the price per student is $1.12, bringing the total to $12.17.


Jameco 2012 Dec 17

Tubes for storing dual-inline package ICs (previously used).

Item Jameco # Quantity Unit Cost Total
*IC DIP RAIL,.300 WIDTH,PLAST.
FOR 8,14,16,18,20,22-PIN IC’S
29516 10 $0.22 $2.20
@ RAIL/TUBE STOPS,RUBBER,GRAY
FOR IC RAILS 29516,AND 29524
29583 100 $0.05 $5.00
personal 1 $4.95 $4.95
CATALOG 82368 1 $0.0001 $0.00
Subtotal: $12.15
Shipping: $5.60
Tax: $0.88
Total for this Order: $18.63

Once again, I added a personal order to avoid a service fee for having an order under $10. Each student should get 1/3 of an IC rail (8¢) and 2 stops (10¢), plus shipping and tax, for a subtotal of 28¢.

The total so far is $12.45


http://www.labandscience.com 2012 Dec 17

Order Information – Order #1164

Qty. Products Total
20 ea. Student Thermometers

$36.40
SubTotal: $36.40
Flat Rate (Best Way): $11.99
Total: $48.39

Each student thermometer costs $2.42, raising the total to $14.87.


parts-express.com 2012 Dec 17

I decided to go with the heavy-duty loudspeaker from Parts Express, so that the students would be able to build a power amp to drive it.  The littler speakers would burn out too easily.  Since this is a “Buyout” the price is substantially less than one would expect for a 10W speaker.  I also tossed in some cheap velcro cable ties—I’ve found them invaluable for keeping my USB cables and power cords organized.

JAMO 30466/30462 2-1/2″ x 4″ Shielded Speaker

The Jamo 30466/30462 2-1/2″ x 4″ speaker utilizes a paper cone with treated foam surround to produce natural, articulate sound reproduction. Small diameter voice coil extends upper frequency response limit. This Jamo speaker is  magnetically shielded allowing it to be used near computer monitors and televisions without distorting the picture. Buyout prices make this shielded Jamo speaker fit perfectly into the budget of any project.

Specifications: • Power handling: 10 watts RMS/20 watts max • VCdia: 9/16″ • Le: 0.44 mH • Impedance: 8 ohms • Re: 6.74 ohms • Frequency response: 191-10,500 Hz • Fs: 191 Hz • SPL: 83 dB 1W/1m • Vas: 0.025 cu. ft. • Qms: 7.35 • Qes: 3.52 • Qts: 2.38 • Xmax: 0.5 mm • Dimensions: Overall diameter: 2-5/8″ x 4-1/8″, Cutout diameter: 2-3/8″ x 3-3/4″, Depth: 1-7/8″.

Item Qty. Price Total
JAMO 30466/30462 2-1/2″ x 4″ Shielded Speaker
Part Number: 299-919
20 $0.78 $15.60
Hook & Loop 6″ Cable Ties 6-Pack Assorted Colors
Part Number: 080-916
20 $0.59 $11.80
FedEx Home Delivery $17.64
Order Total: $45.04

This purchase adds $2.25 per student, bring the total to $17.12 per student.


meerkatsystems 2012 Dec 17

Product Price Quantity Subtotal
Solderless Breadboard – 830 Tie Points, package of 20 items @4.70 each.
SKU: 10-000-023
4.70 20 94.00
Shipping Destination
Country:
Postal Code
Subtotal: $94.00
Tax: $0.00
Shipping & Handling UPS Ground $15.85
Include Insurance
Insurance provided by carrier for free
Total: $109.85

The breadboard adds another $5.49, bringing the total to $22.61/student.


sparkfun 2012 Dec 17

I decided to add a low-cost solder sucker to the tools list.

Product Desc Quantity Price
Product TOL-00082
Solder Vacuum
20 $71.20
($3.56 each)
Product TOL-08696
Wire Strippers 30AWG
20 $89.20
($4.46 each)
Product TOL-08793
Needle Nose Pliers
20 $35.20
($1.76 each)
Product TOL-08794
Diagonal Cutters
20 $35.20
($1.76 each)
Totals
Subtotal $230.80
Shipping/Handling $15.57
Total: $246.37

The tools from SparkFun add another $12.32 per student, raising the total to $34.93.


Amazon

Items Ordered Price
1 of: 100 PCS Alligator Clip Clamp Assortment
Condition: New
Sold by: Deerso (seller profile)
$13.95
2 of: Vermed SilveRest Resting EKG Electrode, 1 3/8″ Vinyl Tape, 100/bx
Condition: New
Sold by: MedexSupply (seller profile)
$20.59
1 of: Steel Machine Screw, Metric, Pan Head, Phillips Drive, Zinc Plating Finish, M3-0.5, 16mm Length, Pack Of 100
Condition: New
Sold by: Amazon.com LLC
$6.75
Item(s) Subtotal: $61.88
Shipping & Handling: $6.38
Super Saver Discount: -$6.38
—–
Total before tax: $61.88
Estimated tax to be collected: $0.57
—–
Grand Total: $62.45
Items Ordered Price
2 of: Standard 3/16″ Flexible Airline Tubing for Aquariums, 25 feet
Condition: New
Sold by: CNZ Lighting (seller profile)
$4.90
Item(s) Subtotal: $9.80
Shipping & Handling: $0.00
—–
Total before tax: $9.80
Estimated tax to be collected: $0.00
—–
Grand Total: $9.80
Items Ordered Price
20 of: 1/4W Metal Film Resistor Assorted Kit 112ValuesX10pcs
Condition: New
Sold by: DIYGSM Electronics (seller profile)
$12.90
Item(s) Subtotal: $258.00
Shipping & Handling: $4.49
—–
Total before tax: $262.49
Estimated tax to be collected: $0.00
—–
Grand Total: $262.49

The machine screws are for the pressure sensors, so I should get reimbursed for 24 of them, but at 7.32¢ each, I can’t see doing the paperwork for $1.76.

Item Qty Subtotal
 alligator clips  4  56¢
 EKG electrodes  9  93¢
 3/16″ air-line tubing  2′  39¢
 resistors  1120  $13.12

The Amazon order adds another $15.01, bringing the total to $49.94 per student.  It bothers me a bit that the students are buying a lifetime supply of resistors and will only be using about 1% of them in the course.  The problem is that determining which 1% of the resistors they’ll use is part of the design exercise of the course.  If we were using stable pairing of students for the duration of the course, we could get away with students sharing parts kits, but because the students will have different partners for each lab, each student needs to be fully equipped.  For the tools, I have no qualms—the prices are very low and students should acquire tools, but the resistors are a big chunk of change for something that they use so little of.


Digikey 2012 Dec 24

Index Quantity Part Number Description Customer Reference Available Quantity Backorder Quantity Unit Price Extended Price
1 100 H762-ND HEX NUT 0.217″ M3 100/PK M3 NUTS 100
Immediate
0 0.03840 $3.84
2 12 MPX2053DP-ND SENSOR DIFF PRESSURE 7 PSI MAX PRESSURE SENSOR 12
Immediate
0 11.52600 $138.31
3 112 A98335-ND TERM BLOCK 4POS SIDE ENT 2.54MM 4-LONG 0.1″ SCREW TERMINAL 112
Immediate
0 0.58120 $65.09
4 132 445-8404-ND CAP CER 4.7UF 10V 10% RADIAL 4.7UF CAPACITOR 132
Immediate
0 0.16000 $21.12
5 40 MCP6004-I/P-ND IC OPAMP QUAD 1.8V 14DIP MCP6004 QUAD OP AMP 40
Immediate
0 0.36000 $14.40
6 25 NTD5867NL-1GOS-ND MOSFET N-CH 60V 18A 43MOHM IPAK NFET 18A 25
Immediate
0 0.38240 $9.56
7 25 NTD2955-1GOS-ND MOSFET P-CH 60V 12A IPAK PFET 12A 25
Immediate
0 0.49920 $12.48
8 40 INA126PA-ND IC OPAMP INSTR 200KHZ SGL 8DIP INSTRUMENTATION-AMP 40
Immediate
0 2.25000 $90.00
9 20 BC2646-ND THERMISTOR NTC 10K OHMS WIRE THERMISTOR 20
Immediate
0 0.76500 $15.30
10 20 102-1721-ND MIC COND ANALOG OMNI -44DB ELECTRET MICROPHONE 20
Immediate
0 0.74600 $14.92
11 20 754-1468-ND PHOTOTRANSISTOR IR NPN 940NM PHOTOTRANSISTOR 20
Immediate
0 0.18700 $3.74
12 25 296-1577-5-ND IC HEX SCHMITT-TRIG INV 14-DIP SCHMITT TRIGGER INVERTER 25
Immediate
0 0.27520 $6.88
13 25 754-1606-ND LED RED DIFF 3MM 625NM RED LED 25
Immediate
0 0.08080 $2.02
14 25 754-1591-ND LED GREEN CLEAR 3MM 565NM GREEN LED 25
Immediate
0 0.08080 $2.02
15 25 CT94EW103-ND TRIMMER 10K OHM 0.5W TH 10K TRIM POT INLINE 25
Immediate
0 1.25160 $31.29
16 20 475-2943-ND LED IR EMITTER 950NM IR EMITTER 20
Immediate
0 0.19900 $3.98
Subtotal $434.95
Shipping $12.40
Sales Tax $36.97
Total $484.30

I didn’t know the shipping cost for the Digikey order until they actually sent it (2012 Dec 26). For some of the parts there was a good price break at 25 parts, and so I ordered that many, so that the per student price would be lower, even if it meant I ended up paying for extras that I don’t really need.  Shipping and tax add 11.35% to the cost of parts in the Digikey order.

I believe that this order completes my purchases before the beginning of the course, not counting the plastic bags to package the kits in.

Per student breakdown of costs:

Quantity Part Number Description Customer Reference Unit Price Extended Price
5 A98335-ND TERM BLOCK 4POS SIDE ENT 2.54MM 4-LONG 0.1″ SCREW TERMINAL 0.58120 $2.91
6 445-8404-ND CAP CER 4.7UF 10V 10% RADIAL 4.7UF CAPACITOR 0.16000 $0.96
2 MCP6004-I/P-ND IC OPAMP QUAD 1.8V 14DIP MCP6004 QUAD OP AMP 0.36000 $0.72
1 NTD5867NL-1GOS-ND MOSFET N-CH 60V 18A 43MOHM IPAK NFET 18A 0.38240 $0.38
1 NTD2955-1GOS-ND MOSFET P-CH 60V 12A IPAK PFET 12A 0.49920 $0.50
2 INA126PA-ND IC OPAMP INSTR 200KHZ SGL 8DIP INSTRUMENTATION-AMP 2.25000 $4.50
1 BC2646-ND THERMISTOR NTC 10K OHMS WIRE THERMISTOR 0.76500 $0.77
1 102-1721-ND MIC COND ANALOG OMNI -44DB ELECTRET MICROPHONE 0.74600 $0.75
1 754-1468-ND PHOTOTRANSISTOR IR NPN 940NM PHOTOTRANSISTOR 0.18700 $0.19
1 296-1577-5-ND IC HEX SCHMITT-TRIG INV 14-DIP SCHMITT TRIGGER INVERTER 0.27520 $0.28
1 754-1606-ND LED RED DIFF 3MM 625NM RED LED 0.08080 $0.08
1 754-1591-ND LED GREEN CLEAR 3MM 565NM GREEN LED 0.08080 $0.08
1 CT94EW103-ND TRIMMER 10K OHM 0.5W TH 10K TRIM POT INLINE 1.25160 $1.25
1 475-2943-ND LED IR EMITTER 950NM IR EMITTER 0.19900 $0.20
Subtotal $13.57
Shipping+tax $1.54
Total $15.11

This order brings the total per student to $65.05

The amount I need to be reimbursed for the pressure sensors and boards is

Quantity Vendor Description Unit Price Extended Price shipping+tax total
 12  iteadstudio  PC boards  99¢  $11.88  $2.35  $14.23
24  amazon  M3x16mm screws 6.75¢ $1.62 $0.14 $1.76
12  digikey  4-long screw terminals 58.12¢ $6.97 $0.79 $7.76
12  digikey  4.7µF capacitor 16¢ $1.92 $0.22 $2.14
12  digikey  pressure sensor $11.526 $138.31 $15.70 $154.01
48  digikey  M3 nuts 3.84¢ $1.84 $0.21 $2.05
 TOTAL $162.54 $19.41 $181.95

So the pressure sensors boards will cost $15.16 each for the 12 copies. (Of course, the assembly and testing of the boards will be done by me, which makes the true cost of the boards much higher, but the University is already paying my salary, so there is no additional cost involved there.)


2012 Dec 27

Yesterday I ordered some 2-gallon Ziploc bags to package the student part kits in

Quantity Description Extended Price
1 Ziploc Freezer Bag, 2 Gallon Jumbo, 10-Count(Pack of 3) $13.14
Sales tax $1.12
Total $14.26

The Ziploc bag adds another 48¢ to the per-student cost, bringing the total to $65.53

Several packages arrived today, so I’m now only waiting for the breadboards, the Digikey order, and the Ziploc bags.

The breadboard order was delayed by the seller (meerkatsystems), who apologized for the delay and refunded the shipping charge, which reduces the parts cost by 79¢ per student, to $64.74.  The boards were shipped today and so should arrive by next week, in time to put the parts kits together.  I’ve started on assembling some parts already, like re-distributing the electrolytic capacitors so that each student gets one of each size and putting one 20-pin section of double-sided headers into little plastic bags.  Redistributing the capacitors was tedious—240 pick and place operations from muffin tins on my kitchen table.

 

2013 Jan 4 last-minute order from DigiKey

Index Quantity Part Number Description Customer Reference Available Quantity Backorder Quantity Unit Price Extended Price
1 25 296-6601-5-ND IC DUAL DIFF COMPARATOR 8-DIP LM2903 DUAL COMPARATOR 25
Immediate
0 0.27080 $6.77
Subtotal $6.77
Shipping Estimate
Sales Tax $0.59
Total unknown

I added the comparators to the parts list just days before the class starts, because I switched from class AB amplifiers to class D amplifiers for the power-amplifier lab, and they work much better with a comparator rather than an op amp driving the FETs (we don’t want a low slew rate).

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