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Current Monitors / Sensors/ Detectors Circuits
Sensors / Detectors -- Main Page

Current Monitors / Sensors/ Detectors:  #'s - B      C - G      H - K      L - R     S - Z

 

Last Updated: November 22, 2021 02:42 PM

Circuits Designed by Dave Johnson, P.E. :

Self Powered AC Indicator -  Often there is a need to monitor when AC current flows into a load.  The circuit below works well for this application.  it uses an off-the-shelf torrid type AC-1020 current transformer from Triad, available from Mouser.  A wire carrying the AC current is . . . Hobby Circuit designed by David Johnson P.E.-December, 2007

Self-Powered AC Current Indicator -  Often there is a need to monitor when AC current flows into a load.  The circuit below works well for this application.  it uses an off-the-shelf torrid type AC-1020 current transformer from Triad, available from Mouser.  A wire carrying the AC current is. . . Circuit by David Johnson P.E.-December, 2007

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-778-8407




Links to electronic circuits, electronic schematics and designs for engineers, hobbyists, students & inventors:

Scheme provides high-side current-sensing for white-LED drivers -  19-Feb-04 EDN Design Ideas:  White LEDs find wide use in backlighting color-LCD screens in most portable devices, such as cellular phones, PDAs, and MP3 players.  Multiple LEDs often connect in series to ensure that the same current flows through every LED.  To forward-bias these LEDs, a voltage of 10 to 16V comes from an inductor-based boost regulator, such as an SP6690 Design by Dimitry Goder, Sipex Corp, San Jose, CA

Secondary-Side AC Breaker -  The LT2940 measures a high side current and a differential voltage, multiplies them and outputs a current proportional to instantaneous power.  Bidirectional high side currents and bipolar voltage differences are correctly handled by the four-quadrant multiplier and push-pull output stage, which allows the LT2940 to indicate__ Linear Technology/Analog Devices App Note, Apr 26th 2010

Self Powered AC Indicator -  Often there is a need to monitor when AC current flows into a load.  The circuit below works well for this application.  it uses an off-the-shelf torrid type AC-1020 current transformer from Triad, available from Mouser.  A wire carrying the AC current is . . . Hobby Circuit designed by David Johnson P.E.-December, 2007

Self-Powered AC Current Indicator -  Often there is a need to monitor when AC current flows into a load.  The circuit below works well for this application.  it uses an off-the-shelf torrid type AC-1020 current transformer from Triad, available from Mouser.  A wire carrying the AC current is. . . Circuit by David Johnson P.E.-December, 2007

Sense Automobile High-Side Current with Discrete Components -  09/14/12  EDN Design Ideas:  Use this circuit to convert a current into a voltage for measurement.   __ Circuit Design by Larry Beaty, Beatys Mills, Comer, Georgia

Sense High-Side Current -  03/01/01 EDN Design Ideas:  The accurate, high-side, current-sense circuit does not use a dedicated, isolated supply voltage, as some other schemes do.    Design by Bobell

Serves as milliohmmeter -  04/15/04 EDN Design Ideas:  When I was recently debugging a design, I discovered that a short circuit existed from a ground plane to a power plane.  I did not have access to a milliohm meter or an equivalent tester for locating this type of short circuit.  So, I logged onto the internet to find an easily constructible milliohm meter Design by AM Hunt, Lancaster Hunt Systems Ltd, Shepperton, UK

Simple Circuit 500V High Side Current Monitor -  Adding two external MOSFETs to hold off the voltage al-lows the LTC6101 to connect to very high potentials and monitor the current flow.  The output current from the LTC6101, which is proportional to the sensed input volt-age, flows through M1 to create a ground referenced output voltage.  __ Linear Technology/Analog Devices App Note, Mar 30th 2010

Simple Circuit Bidirectional DC Motor Speed Controller -  The LT1970 is a ±500mA power op amp with precise externally controlled current limiting.  Separate control voltages program the sourcing and sinking current limit sense thresholds with 2% accuracy.  Output current may be boosted by adding external power transistors.  __ Linear Technology/Analog Devices App Note, Apr 5th 2010

Simple Circuit Electronic Breaker -  This circuit uses the on-resistance of the MOSFET as the current sensor.  Reset it by removing the input power or the load.  The circuit draws no current unless tripped.   __ Designed by Andrew R. Morris

Simple Circuit provides high-side current sensing -  10/12/00 EDN Design Ideas:  in power supplies or battery chargers, you often need information about the current flowing in the high-side rail.  Figure 1 shows a common circuit for obtaining this information.  The circuit provide as a groundreferenced voltage pr Design by M Ossmann and B Kazay, Aachen University of Applied Sciences, Germany

Simple Circuit serves as milliohmmeter -  04/15/04 EDN Design Ideas:  When I was recently debugging a design, I discovered that a short circuit existed from a ground plane to a power plane.  I did not have access to a milliohm meter or an equivalent tester for locating this type of short circuit.  So, I logged onto the internet to find an easily constructible milliohm meter Design by AM Hunt, Lancaster Hunt Systems Ltd, Shepperton, UK

Simple Circuit Ways to Measure Current-LTC6101, LTC6102, LTC6103, LTC6104 -  Measuring current is one of the basic requirements in many electronic systems; whether for precise control or simple protection of circuit elements.  A family of new devices from has been produced to greatly simplify the measurement of DC or AC current.  Using only external resistors, each small device can be __ Linear Technology/Analog Devices App Note, Jon Munson-Applications Engineer-Amplifier Products Mar 15th 2009

Simplified DC Motor Torque Control -  The LT6109 is a complete high side current sense device that incorporates a precision current sense amplifier, an integrated voltage reference and two comparators.  Two versions of the LT6109 are available.  The LT6109-1 has the comparators connected in opposing polarity and the LT6109-2 has the comparators connected in the same __ Linear Technology/Analog Devices App Note, Sep 7th 2011

Simplified DC Motor Torque Control -  The LT6108 is a complete high side current sense device that incorporates a precision current sense amplifier, an integrated voltage reference and a comparator.  Two versions of the LT6108 are available.  The LT6108-1 has a latching comparator and the LT6108-2 has a non-latching comparator.  in addition, the current sense amplifier __ Linear Technology/Analog Devices App Note, Sep 7th 2011

Simplified DC Motor Torque Control-LT6108 -  The LT6108 is a complete high side current sense device that incorporates a precision current sense amplifier, an integrated voltage reference and a comparator.  Two versions of the LT6108 are available.  The LT6108-1 has a latching comparator and the LT6108-2 has a non-latching comparator.  in addition, the current sense amplifier__ Linear Technology/Analog Devices App Note, Sep 7th 2011

Simplified DC Motor Torque Control-LT6109 -  The LT6109 is a complete high side current sense device that incorporates a precision current sense amplifier, an integrated voltage reference and two comparators.  Two versions of the LT6109 are available.  The LT6109-1 has the comparators connected in opposing polarity and the LT6109-2 has the comparators connected in the same__ Linear Technology/Analog Devices App Note, Sep 7th 2011

Solar Current Meter -  This circuit is used to measure the current from a solar panel.  it has very low power loss for currents in the 0-10A range.  it also works as a general purpose DC current meter.  The circuit can be used on either the positive or negative side of a DC circuit __ Designed by G. Forrest Cook

Solenoid Current Monitor for Ground Tied Solenoid -  The common mode inputs to the LT1999 switch between Vs and one diode drop below ground.  The LT1999 is a high speed precision current sense amplifier, designed to monitor bidirectional currents over a wide common mode range.  The LT1999 is offered in three gain options: 10V/V, 20V/V, and 50V/V.  The LT1999 senses current via__ Linear Technology/Analog Devices App Note, Nov 16th 2010

Solenoid is Pulled High to 24V, Freewheels Low to a Schottky BeLow Ground -  The large input common mode range of the LT6105 makes it suitable for monitoring currents in quarter, half and full bridge inductive load driving applications.  This circuit shows an example of a quarter bridge.  The MOSFET pulls down on the bottom of the solenoid to increase solenoid current.  it lets go to decrease current, and __ Linear Technology/Analog Devices App Note, Mar 31, 2010

Split or Single Supply Operation, Bidirectional Output into A/D -  in this circuit, split supply operation is used on both the LT1787 and LT1404 to provide a symmetric bidirectional measurement.  in the single-supply case, where the LT1787 pin 6 is driven by VREF, the bidirectional measurement range is slightly asymmetric due to VREF being somewhat greater than mid-span of the ADC input range.  __ Linear Technology/Analog Devices App Note, Mar 31, 2010

Temperature Monitoring with an NTC Thermistor While Measuring Load Current & LTC4151 Supply Current -  The LTC4151 is a high side power monitor that operates over a wide voltage range of 7V to 80V.  in default operation mode, the onboard 12-bit ADC continuously measures high side current, input voltage and an external voltage.  Data is reported through the i2C interface when polled by a host.  The LTC4151 can also perform on-demand__ Linear Technology/Analog Devices App Note, Apr 26th 2010

The LT6105 Can Monitor the Current of Either Positive or Negative Supplies, Without a Schematic Change. -  Positive or negative current flow is measured by just swapping inputs, -iN connected to most negative side of sense resistor.  +iN is connected to most positive side of sense resistor.  __ Linear Technology/Analog Devices App Note, Jun 29th 2012

Transmitter Accurately Transfers Voltage Input -  15-May-03 EDN Design Ideas:  When you connect remote sensors to a central process controller, a simple, robust, and commonly used interface is the 4- to 20-mA loop.  The advantages of this current loop include the simplicity of just two twisted wires that share both power and signal, the loop's high noise immunity in harsh environments, and the de facto loop standard within the process-control industry Design by Clayton Grantham, National Semiconductor, Tucson, AZ

Two Sensors Measure Three Line Current -  09/01/95 EDN Design Ideas:  An old technique updated for modern requirements allows you to measure all three line currents in a three-phase system.  You perform this measurement using two current transformers (CTs) and three ammeters.  The original technique appeared in Alternating-Current Machines by George Mueller (McGraw-Hill, 1952).  The method works equally well with modern current sensors.  Figs 1 and 2 illustrate the technique.    Design by Henno Normet, Tavares, FL

Ultraprecise Current Sensing with LTC6102 -  Very low input offset allows using low value resistors while maintaining high measurement resolution.  Using low value also reduces power losses and temperature rise.  __ Linear Technology/Analog Devices App Note, Jul 2, 2012

Understanding Electricity-an analogy with water -  (good start for beginners)  __ Designed by Richard Torrens

Voltage Controlled Current Source -  Adding a current sense amplifier in the feedback loop of an adjustable low dropout voltage regulator creates a simple voltage controlled current source.  The range of output current sourced by the circuit is set only by the current capability of the voltage regulator.  The current sense amplifier senses the output current and __ Linear Technology/Analog Devices App Note, Mar 31, 2010

Voltage Controlled Current Source with Ground Referred Input & Output -  A flying capacitor device such as the LTC1043 can produce a precision voltage differential over a wide common mode range.  Here it converts a ground referred input voltage directly to a differential voltage across a fixed resistor which then forces a precise current sourced at the circuit output.  __ Linear Technology/Analog Devices App Note, Jun 21, 2011

Voltage reference improves JFET -  26-Oct-00 EDN Design Ideas:  The common JFET current-source in Figure 1a has average output impedance and depends heavily on the JFET's VP and iDSS variations.  These manufacturing variations limit the initial accuracy of the current setpoint that the circuit can obtain with a fixed R1.  Most users of JFET current-sources sample VPPDF has several circuits, scroll to find this one Design by Clayton Grantham, National Semiconductor, Tucson, AZ

Wide Input Range 10W PWM Heat Source -  The LT2940 measures a high side current and a differential voltage, multiplies them and outputs a current proportional to instantaneous power.  Bidirectional high side currents and bipolar voltage differences are correctly handled by the four-quadrant multiplier and push-pull output stage, which allows the LT2940 to indicate__ Linear Technology/Analog Devices App Note, Apr 26th 2010

Wire Loss Compensation using a Current Referenced LDO -  This circuit shows a cable drop compensation circuit using a current referenced regulator, the LT3080.  A precision 10μA set current, iSET, is sourced through two series connected resistors to program the output voltage for the remote load.  To compensate for the load connecting cable drop requires sourcing an additional __ Linear Technology/Analog Devices App Note, Jun 19th 2013


Current Monitors / Sensors/ Detectors:  #'s - B      C - G      H - K      L - R     S - Z


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