Bill of Materials 



MOUNTING THE COMPONENTS 



The following components and supplies 

 are needed: 



Item 



Approximate 

 price 



SW 1-1-7 = 8 pole, 4 gang, mini- 

 ature, 5 pos . wafer 

 switch (phenolic) $ 3 . 12 



Bi, Bo = 2 - ZM-9 mercury 



batteries, or equivalent 1.02 



Battery holder, for above batteries .38 



B3 = Battery, 6 volt, Z4 or 



equivalent .63 



Battery holder, type 175 .24 



M = 1 - 0-50 microammeter 16 .76 



Tr = 1 transistor 2N34, or 



equivalent 3 . 20 



1 - Plug, 4 contact. Cannon 



XLR-4-12 C, or equivalent 1.20 



1 -Socket, 4 contact, XLR-4-13 1.93 



1 - Minibox 7x5x3 inches 1 . 78 



R-1 = 1 - 10 -turn micropot, Borg 



model HUB, 5000 ohms, 



or equivalent 10.68 



1 - Microdial for above, Model 



1327, or equivalent 5.82 



7 - Resistors, 1/2 watt, 5% 1.68 



Values: 



R-6, 7= 2 - 100 ohm 



R-8,= 1 - 10 ohm 



R-2, 3, 5 = 3- 1800 ohm, or 



select R-5 (see text) 

 R-4 = 1 - 3600 ohm 

 R-9= 1 - 500 ohm wirewound 



potentiometer 1 . 12 



Cable, 4cond., any length desired 

 about . 10 per foot 



2 ft. - 9 wire cable, plastic covered .20 

 1 - pure silver tube 1 inch long by 



3/4 inch diameter 5.00 



1 - piece of platinum foil about 1/2 



inch square, approximately .004 

 inch thick. Priced according to 

 market (about $2 - $3). 



3 tubes epoxy 3.00 

 Th = 1 - Thermistor, 1000 ohm at 



25'" C, Veco 31A11 or 



equivalent 2.85 



2 - Small plastic baby bottles, 1 



with cap and nipple .40 



Total 61.01 



The instrument case (minibox) should 

 be drilled to accommodate the switch, potenti- 

 ometer R-9, potentiometer R-1 and its counter 

 dial, and the meter as shown in Photograph 1. 

 Follow the instructions included by the manu- 

 facturers for the switch, micropot and dial . 

 The mounting of the meter and R-9 is obvious. 

 Only the 1/2 -inch hole for mounting the micro- 

 pot and dial is critical. 



After these major components are 

 mounted on the cover plate, drill holes in the 

 back plate and attach battery holders as shown 

 in Photograph 2 . Be sure to place the holders 

 so that they do not interfere with other com- 

 ponents when closing the case. The 4-way 

 chassis plug for the electrode cable can be 

 mounted on either end or side of case, depend- 

 ing on preference . The mounting and arrange- 

 ment of components are not critical and can be 

 done as preferred by the builder, within the 

 limits of the space in the case. 



Photograph 1: — View of complete 

 oxygen-temperature meter. 



