Geller Labs
Geller Labs


JCan Parts List

1 1 Q1 BF244A Mouser 512-BF244A, Fairchild N-Channel JFET (you might want to buy 5 to 10 to observe differences between production JFETs).

2 1 U1 LT10281 Linear Technology Ultra low noise OpAmp, Digikey LT1028CN8-ND, or Analog Devices AD797, Digikey AD797AN-ND

3 1 U2 LT1357 Linear Technology high speed OpAmp, Digikey LT1357CN8-ND

4 1 Q1 Socket Socket use pin sockets, same as item 14; a conventional transistor socket adds to much input capacitance.

5 2 U1,U2 Socket Mill-Max DIP Low Profile, Mouser 575-193308

6 4 J1,2,3,4 slit socket AMP gold #18 solder D-sub socket, Mouser 571-665693, Allied 512-2478

7 1 R5 10 Meg We use Vishay VR25 BCC 5043D metal film resistor in our kits and assembled JCan, Mouser 594-5043DM10M00J (available only in large quantities). Also, RN1/4T1 1% 9.76M metal film, Allied Electronics 832-1111 or any other near valued 10 Meg resistor (8 to 10 Meg, preferably metal film).

8 3 R2,3,6 1.0 k ohms 1% metal film, Xicon 1/4W (Mouser), For ex: Mouser ME271-1.0k (or, test and select for a V drain to source of about 4 or 5 volts).

9 Despite hours of proof reading, we appear to have skipped a number :)

10 2 R1,7 39.0 k ohms 1% metal film, Xicon 1/4W (Mouser)

11 1 R9 402 ohms 1% metal film, Xicon 1/4W (Mouser)

12 1 R8 10 ohms 1% metal film, Xicon 1/4W (Mouser)

13 1 R4 100 k ohms 1% metal film, Xicon 1/4W (Mouser)

14 9 pin sockets SIP We use a gold MILL-MAX pin jack, PN 0501-0-15-15-30-27-04-0; a SIP type breakaway sockets such as Mouser 575-643166 or equivalent, can also be used for R2, Q1, TP1, TP1 common, Vout, and Vout common.

15 2 C2,15 1μf Panasonic film capacitor, ECQV1J105M, Digikey P4548-ND

16 1 C1 0.1 μf Panasonic film capacitor, ECQ-V1H104JL, Digi-Key P4525-ND

17 1 C3 0.001 μf (1nf) Panasonic film capacitor, ECQ-B1H102JF, P4551-ND

18 3 C4,10,14 150 pf AVX ceramic capacitor, 150 pf, 100V 10%, Digikey 478-3166-ND

19 5 C5,8,9,11,13 0.1 μf Kemet ceramic, Mouser 80-C315C104M5U

20 1 C6 150 μf Nichicon 150 μf, 50V, low impedance electrolytic, Mouser UHE1H151MPD

21 1 PCB Geller Labs JCan PCB

22 1 ½ Gallon Paint 30W12A 1/2 Gallon "Short" Tin Can w/ Lid Unlined, 6-5/8" x 4", The Cary Company, 1195 W. Fullerton Ave, Addison, IL 60101

23 2 9V battery clips Digikey 2240K-ND or equivalent

24 2 Double sided tape 3M 4013 1/2 wide foam mounting tape

25 2 Alkaline 9V batteries Rayovac 9V2 A1604-2 or equivalent

26 Resistors under test A selection of metal film resistors from about 1 k to about 300 k for calibrating the JCan, we use the following collection in our “cal. pack”: 49.9, 100, 200, 400, 1k, 2.2k, 4.9k, 10k, 22k, 49.9k, 100k, 200k, 300k, 402k, 499k. The exact values are unimportant. Actual values, measured with an ohmmeter can improve your calibration data.

27 Resistors under test A selection of different types of resistors, preferably in the range of 10k to 100k, such as carbon composition, carbon film, metal film, and wirewound for testing and comparing noise levels under power (one resistor to V+ filtered and a like type and valued resistor from input to common); we use 82k to extend battery life.

28 4 4-40 standoffs general purpose hardware (if you experiment with nylon standoffs, note that paint can common is made through one of the conductive metal corner posts).

29 4 4-40 screws general purpose hardware

30 4 4-40 nuts / lock washers general purpose hardware

31 1 DPDT slide switch ITT (formerly C&K) 1201M2S3CBE2, Mouser 611-1201M2S3CBE2 or equivalent, 100,000 cycles, has an easy slide action.

32 1 BNC AMP BNC bulkhead solder jack connector, AMP 31-10-RFX, Mouser  523-31-10-RFX


33 1 LED Any LED visible at about 50 to 100 µA (to save battery life), some ultra brightness types work well.

34 1 RG-174 Short length of coaxial cable or (short) twisted wires made from the excess ends of the 9V battery clip wires.


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