Issue link: https://iconnect007.uberflip.com/i/1309864
72 PCB007 MAGAZINE I NOVEMBER 2020 etches, and catalysts. Table 2 shows some of the analyses of PCB chemis- tries using the Agilent DAS as com- pared to manual titration or atomic absorption. DAS spectra scans of three compo- nents of a nickel plating bath and pal- ladium in catalyst and the differences for different concentrations of nickel and palladium can be found in Auto- mation and Advanced Procedures in PCB Fabrication. 4. Electronic Coulemetric Ampere-hour sensors accumulate the total DC current used for the time employed (Figure 9). This device can automatically replenish a chemical based on the current-time setpoint. The integral pump runs for a set num- ber of seconds (2.3 ml per second) if energized and calibrated for any size power supply using a 50 mv shunt. A unit can be built for less than $5, or purchased. Table 2: Application of the Agilent DAS for PCB chemical analysis compared to the older techniques of titration and atomic absorption spectrophotometer [1 & 2] . Figure 9: Ampere-hour meters can be purchased or built very inexpensively with IC op-amps or Raspberry Pi units.