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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 03:00 PM

Circuits Designed by Dave Johnson, P.E. :
Monitors AC Current -  This circuit uses a small AC current transformer from Magnetek to produce an isolated voltage proportional to the AC current in the primary winding.  The transformer contains a single turn primary with a low 0.001-ohm resistance.  it can easily handle 30 . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Monitors Pump Motor -  This circuit solves this problem in a novel way.  it clips on the outside of the pump motor’s power cable and provides a transistor switch closure whenever the circuit detects current flowing to the motor.  The circuit draws so little current that a small lithium cell will power the circuit for yearsCircuit Solution by David A. Johnson P.E.-November, 2004

Pump Motor Monitor -  This circuit can turn on a light or sound a beeper, whenever an AC line powered pump motor turns on.  it is designed to detect the motor current using a small inductor placed on the outside of the motor’s power cable.  No direct wire contact is needed. . . Circuit by David Johnson P.E.-November, 2004

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:

Load Monitor Alarms Above 60W -  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

Low Power, Bidirectional 60V Precision Hi Side Current Sense -  Using a very precise zero-drift amplifier as a pre-amp allows for the use of a very small sense resistor in a high voltage supply line.  A floating power supply regulates the voltage across the pre-amplifier on any voltage rail up to the 60V limit of the LT1787HV circuit.  Overall gain of this circuit is 1000.  A 1mA change in __ Linear Technology/Analog Devices App Note, Mar 31st 2010

Low Side Current Sense -  Sensing the amount of current through a load on the low side has the disadvantage of raising the return connection to the load from ground.  The advantage of such an approach is that it is very easy to implement using a basic non-inverting gain stage.  The LTC6081 operates linearly down to ground also in this single supply example.  __ Linear Technology/Analog Devices App Note, Mar 16th 2010

LTC2990-Motor Protection/Regulation -  The LTC2990 is used to monitor system temperatures, voltages and currents. Through the i2C serial interface, the device can be configured to measure many combinations of internal temperature, remote temperature, remote voltage, remote current and internal VCC. __ Linear Technology/Analog Devices App Note, Oct 26th 2010

LTC2991 Octal I2C Voltage, Current & Temperature Monitor-Video Product Brief -  The LTC®2991 is used to monitor system temperatures, voltages and currents.  Through the i2C serial interface, the eight monitors can individually measure supply voltages and can be paired for differential measurements of current sense resistors or temperature sensing transistors.  Additional measurements include internal temperature __ Linear Technology/Analog Devices App Note, Chris Gobok-Product Marketing Engineer Sep 13th 2011

Measures Capacitance or Inductance -  10/21/10 EDN Design Ideas:  Use instruments you already have and a few equations when you don’t have a capacitance meter.   Design by Jim McLucas, Broomfield, CO

Monitor Leakage Current -  06/21/01 EDN Design Ideas:  The residual-current circuit breaker in Figure 1 continuously monitors the supply lines for any leakage current and immediately disconnects the supply if necessary.  Load-supply wires, both live and neutral, pass through the magnetic core of the CR4311-5 Design by Sharath Kumar, Gemplus R&D Centre, Dubai, United Arab Emirates

Monitors AC Current -  This circuit uses a small AC current transformer from Magnetek to produce an isolated voltage proportional to the AC current in the primary winding.  The transformer contains a single turn primary with a low 0.001-ohm resistance.  it can easily handle 30 . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Monitors Pump Motor -  This circuit solves this problem in a novel way.  it clips on the outside of the pump motor’s power cable and provides a transistor switch closure whenever the circuit detects current flowing to the motor.  The circuit draws so little current that a small lithium cell will power the circuit for yearsCircuit Solution by David A. Johnson P.E.-November, 2004

MOSFET Current Sensing -  Method of mirror current sensing a MOSFET __ Designed by Richard Torrens

Motor Monitor with 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

Motor Protection/Regulation -  The LTC2990 is used to monitor system temperatures, voltages and currents. Through the i2C serial interface, the device can be configured to measure many combinations of internal temperature, remote temperature, remote voltage, remote current and internal VCC. __ Linear Technology/Analog Devices App Note, Oct 26th 2010

Motor Protection/Regulation-LTC2991 -  The LTC2991 is used to monitor system temperatures, voltages and currents.  Through the i2C serial interface, the eight monitors can individually measure supply voltages and can be paired for differential measurements of current sense resistors or temperature sensing transistors.  Additional measurements include internal temperature __ Linear Technology/Analog Devices App Note, Sep 7th 2011

Multi-decade current Monitor the epitome of simplicity -  EDN Design Ideas:  02/06/2017    This DI will likely make the simplest piece of T&M gear on your bench Design by Nick Cornford

Optocoupler extends high-side Current-sensorto 1 kV -  03/01/01 EDN Design Ideas:  The task of sensing dc current at high voltage is often problematic.  Most high-side current-sensing ICs  available off the shelf are good only to 30 or 40V.  Combining an optocoupler with such an IC yields a sensing circuit in which the only limitation of the high-side voltage is the optocoupler's standoff voltage (Figure 1).   Design by Roger Griswold

Overcurrent & Undervoltage Battery Fault Protection -  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

Overcurrent Battery Fault Protection -  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

Precision Current Monitoring for Electric Motors, Solenoids & Inductive Loads -  Current information in electric motors and solenoids provides important insight into power output and system health.  Electric motor and solenoid driving circuits and the devices themselves create a challenging environment for operation of current monitoring circuits, with large common mode voltage shifts, fast switching currents __ Linear Technology/Analog Devices App Note, Culyer Latorraca Mar 21st 2011

Precision Current Sink -  A non-inverting amplifier configuration can force an input control voltage across a ground referred resistor.  This creates a precise amount of current flow.  This current must be sunk by the external transitors so the same amount of current flows to ground from a positive supply referred load circuit.  __ Linear Technology/Analog Devices App Note, Jun 21, 2011

Precision High Voltage High Side Load Current Monitor (1754) -  The LT6016/LT6017 are dual and quad rail-to-rail input operational amplifiers with input offset voltage trimmed to less than 50μV.  These amplifiers operate on single and split supplies with a total voltage of 3V to 50V and draw only 315μA per amplifier.  The Over-The-Top input stage of the LT6016/LT6017 is designed to __ Linear Technology/Analog Devices App Note, Dec 4th 2012

Provide High-Side Current-sensing -  04/24/97  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 ground-referenced voltage proportional to the current Design by M Ossmann

Provide High-Side Current-Sensing for White-LED Drivers -  02/19/04  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  Design by Dimitry Goder, Sipex Corp, San Jose, CA

Pump Motor Monitor -  This circuit can turn on a light or sound a beeper, whenever an AC line powered pump motor turns on.  it is designed to detect the motor current using a small inductor placed on the outside of the motor’s power cable.  No direct wire contact is needed. . . Circuit by David Johnson P.E.-November, 2004

Pushbutton replaces rotary switch -  26-Oct-00 EDN Design Ideas:  The problem of setting any one of four modes of aµC-operated process has a straightforward solution  Have the µC check the states of some 4 bits of aµC.    Design by Abel Raynus, Armatron International Inc, Melrose, MA

Reconstruct the Input Current In a Grounded-Impedance Current Sensor -  09/05/12  EDN Design Ideas:  Measure the current into an impedance by reconstruction with current mirrors.   Design by Abhirup Lahiri, New Delhi, India

Resistance, DC Current, AC Current & Frequency & Period Measurement Errors in Digital MultimetersAN-1389-2 -  Application Note__ Aligent


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


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