Web DiscoverCircuits.com

Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com, has 28,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.
We make every effort to link to material posted by the designer. 
Please let us if you would like us to link to your design.

HOME Schematics Discover Forum Hobby Corner Dave's Circuits Electronic Resources Book Corner Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson &
Associates
My eBay Auctions Faraday Touch Switches

Sensors / Detectors: Capacitance Sensors Circuits

Circuits designed by David Johnson, P.E.

Last Updated on: Friday, March 12, 2010 12:07 PM

The contents & graphics of Discovercircuits.com are copyright protected.
LINKING to Dave's circuits is permitted but DO NOT COPY any files to your WEB SITE server


  • 5V Capacitance Touch Activated Monetary Switch
    This circuit is discussed in more detail in the section on Capacitance Proximity Switch Technology. The circuit is powered from a standard +5v supply. It has both a source and sink output that change state whenever a metal button connected to the circuit is touched. An earth ground reference is required.

  • 5-Volt Momentary Operation Touch Switch
    This simple circuit uses a single IC to form a nice touch switch circuit.  A single transistor forms the remote active switch sensor.  Multiple switches can be wired in parallel.  The switch circuit can be located about 500 feet from the control circuit
  • Capacitance Type Liquid Level Monitor
    This circuit was originally designed to monitor the level of liquid natural gas in a tank but it can be used to also measure almost any liquid. Two custom insulated metal tubes form a capacitor plate. The capacitance between the two tubes increases as the level of the liquid rises. The circuit converts an increase of capacitance into a positive voltage change. The circuit could be changed to handle almost any scale factor needed.
  • Low Value Capacitance Meter
    This circuit was originally designed to measure the volume of fluid inside a medical syringe.   As designed, it produces a zero to 5 volt output, corresponding to a capacitance change of about 10 picofarads.  With a digital voltmeter, at its output, it can resolve a capacitance change of 0.002 picofarads or 2 femtofarads.  (added 12/04)
  • Precision Low Capacitance Meter   NEW
    This circuit was originally designed to measure the volume of the fluid inside a 10cc syringe.  It used two copper foil strips attached to the outside barrel of the syringe.  The fluid between the two copper strips increases the capacitance. As the fluid volume decreased, the capacitance also decreased.  With the circuit shown below, it is possible to calibrate the circuit, so the voltage produced is proportional to the fluid volume inside the syringe.  With the values shown, the circuit produces a 5v DC output,...
  • Short Range Reflective Object Sensor
    Drawing only 30uA from a 3v supply, this circuit will detect a human finger with a range of about 1 inch.  The sensor uses an inexpensive infrared LED and a matching photo diode.


More Sensors / Detectors: Capacitance Sensors Circuits

Master Category List - Dave's Circuits
 

 
HOME Schematics Discover Forum Hobby Corner Dave's Circuits Electronic Resources Book Corner Contact Info

 Linking is welcomed but COPYING any content or graphics to your web site is expressly prohibited.

 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |    Privacy Policy