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High CMRR Instrumentation Amplifier (Schematic and Layout) design for biomedical applications

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Instrumentation amplifiers are intended to be used whenever acquisition of a useful signal is difficult. IA’s must have extremely high input impedances because source impedances may be high and/or unbalanced. bias and offset currents are low and relatively stable so that the source impedance need not be constant. Balanced differential inputs are provided so that the signal source may be referenced to any reasonable level independent of the IA output load reference. Common mode rejection, a measure of input balance, is very high so that noise pickup and ground drops, characteristic of remote sensor applications, are minimized.Care is taken to provide high, well characterized stability of critical parameters under varying conditions, such as changing temperatures and supply voltages. Finally, all components that are critical to the performance of the IA are internal to the device. The precision of an IA is provided at the expense of flexibility. By committing to the one specific task of
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Water contact indicator tape

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Water contact indicator tape changes from white to red when water contacts the edges of this tape, and stays red even when it dries out. The tape will not change if exposed to high humidity environments, only from liquid water.


Water contact indicator tape is a great way for checking electronic devices or mechanical instruments that are not designed to operate in wet conditions. It is also good for finding water leaking sources.

Further Information  --There is a red dye (in dry form) on the back of the water indicator tape. It is separated from the front of the tape by a white wicking material. When water leaks in from the side of the tape it activates the dye which wicks through to the top side. Because the dye colors the wicking material, it stays red even when the tape dries out. 
Common Specifications
Common specifications for commercially available Water contact indicator tapes are listed below:
  Construction: From top to bottom: Transparent PET top film (Polyester), Backing (Indicator layer), Adhesive (Acrylic), Release liner
  Color: White, turns red permanently when wet
  Dimension: 12 inch x 180 yards
  Adhesion:
(ASTM-D3330, 90° Peel Adhesion, 72 hr dwell)		 Stainless Steel: 82 ozs/in (88 N/100 mm)
Polycarbonate: 47 ozs/in (52 N/100 mm)
  Thickness:
(ASTM D-3652)		 Tape: 0.0090" (0.229 mm)
Release Liner: 0.0020" (0.051 mm)
  Humidity Resistance: 55 °C, 95% R.H.
Applications  
Water contact indicator tape is a great way for a manufacturer whose products may be exposed to water but warranty does not cover water damage to verify a customer’s claims. For example:
  • Mobile phones, 2-way radios, cordless phones, personal communicators, and pagers
  • PDAs, gaming consoles, MP3, and CD players
  • Digital, film, and video cameras
  • Lap top computers and keyboards
  • Rechargeable batteries and chargers
  • Vacuum cleaners
Other possible applications:
  • Locate leaks in roofs, basements, or on pipes
  • Flood or ocean's high tide indication
  • Visual indication that you need to change a baby’s diaper
  • Targets for squirt gun games
  • Embedded in the tag of dry-clean only clothes
  • "Don't walk in with wet feet" warning for possible electrocution