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Tester or Measurement (Instrument) Circuits

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Last Updated: December 07, 2017 02:04 PM
Circuits Designed by Dave Johnson, P.E. :

Energy Harvesting using a Current Transformer -  Energy harvesting is all the rage these days.  With some modern electronics, information from low power sensors can be sent to a distant data collection point using a low power RF transmitter.  To power these remote sensors, various energy sources can be. . . Circuit by Dave Johnson P.E.-January, 2010

Expanded Scale 12v Battery Voltage Monitor -  The circuit below expands the battery voltage monitoring scale for a 12v battery so a more accurate voltage reading can be made.  The numbers printed onto the face of a standard 0v to 5v meter are changed so the scale ranges from 10v to 15v.  http://archil. . . Circuit by David Johnson P.E.-October, 2005

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-368-7747




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

Either indicates 120 VAC or 240 VAC  -  Two LEDs indicate if a power line has 120vac or 240vac voltage on it. . . Circuit by David A. Johnson P.E.-July, 2006

Elecraft XG2 receiver test oscillator -  The Elecraft XG2 is a crystal oscillator with accurate 1 V and 50 V output levels.   it's ideal for receiver test and alignment.  The 1-V output can be used to measure a receiver's sensitivity, while the 50-V output is useful for S-meter calibration.  Switch-selected output frequencies of 3579, 7040, and 14060 kHz provide convenient test signals on 80, 40, and 20 meters; harmonics of these frequencies can be used for measurements on higher bands__ 

Electric field & leakage Detector -  And now for something totally different.  it detects very small currents such as those caused by leakage and changing electric fields __ Designed by Richard Torrens

Electric Field Disturbance Monitor-Alarm Discriminator + Battery Monitor -  This schematic is the alarm discriminator plus the batterry monitor of my "Electric Field Disturbance Monitor".  The system can detect human and animal motion by the electric fields they disturb. . . Circuit by Dave Johnson P.E.-March, 2002

Electric Field Disturbance Monitor-Front End + Power Supply Circuit -  This schematic is the power supply and front-end sections of my field monitor, "Electric Field Disturbance Monitor".  The system can detect human and animal motion by the electric fields they disturb. . . Circuit by David A. Johnson P.E.-March, 2002

Electrical Current Indicator -  I designed this circuit as a simple current indicator for any load ranging from 40 watts to 250 watts.  The circuit turns on a small LED, whenever it detects current flowing to a remote load. . . Circuit by David A. Johnson P.E.-October, 2005

Electro Meter -  This is a simple to measure electrostatic charge circuit.  __ 

Electrodeless Water Level Monitor -  This is an illustration how a laser could be used to count traffic and measure the speed of each car passing through the sensor area. . . Circuit by Dave Johnson P.E.-July, 2006

Electroluminescent Wire Sequencer -  Assembly and Operation of the SEQ5 ELWire Sequencer __ Designed by John DuBois

Electrolytic Capacitor Reformer & Tester -  Got a bunch of old electrolytic capacitors you'd like to use but don't know if they are any good? Or do you need to re-form the electrolytics in an old valve amplifier or vintage radio set? This Electrolytic Capacitor Reformer and Tester will do the job for you, at any of 11 different standard voltages from 10V to 630V.__ SiliconChip

Electrolytic Capacitor Reformer & Tester, Pt.2 -  Last month we introduced our new electrolytic capacitor reformer and tester - ideal for anyone working with vintage radios, valve equipment or indeed the hobbyist who has gathered a collection of electrolytics over the years.  Now you can not only test them, you can (usually!) breathe new life into them if they've suffered from the ravages of time! __ SiliconChip

Electrolytic Capacitor Tester -  Using this electrolytic capacitor tester you can detect leaky and dead (open) electrolytic capacitors.  it operates based on the time constant (T) of the capacitor when it is charged up to...__ Electronics Projects for You

Electrolytic capacitor Tester -  Firstly, we will describe the "add-on" version for the 5x7 Display as this is the cheapest version and, quite frankly, it only deserves a few dollars as a piece of test equipment.  it's "all the rage" to have an Electrolytic Tester for servicing equipment and yet I have serviced over 36, 000 appliances without one.  Possibly it took me a long time to realise electrolytics have the capability of drying out because old-style electros were inherently __ Designed by Collin Mitchell

Electromagnetic field Detector -  This circuit is sensitive to low frequency electromagnetic radiation and will detect for example hidden wiring or the field that encompasses a transformer.  Pickup is by a radial type inductor, used as a probe which responds well to low frequency changing magnetic and electric fields.  Ordinary headphones are used to for detection.  The field that surrounds a transformer is heard as a50 or 60Hz buzz.     __ Designed by Andy Collison

Electromagnetic Field Probe Version 2 -  An electromagnetic field probe designed to detect changing electric and magnetic fields.  The probe has switchable gain, a frequency response up to 400kHz and independent audio and meter monitoring.   __ Designed by Andy Collison

Electromagnetic Field Probe with Meter Output -  This tester is designed to locate stray electromagnetic (EM) fields.  it will easily detect both audio and RF signals up to frequencies of around 100kHz.  Note, however that this circuit is NOT a metal detector, but will detect metal wiring if it conducting ac current.  Frequency response __ Designed by Andy Collison

Electromagnetic Levitator -  The model of a small electromagnetic levitation device will be introduced in theOne of the significant parts of the model is the feedback circuit.  it __ Designed by Tom Hron

Electromagnetic Ring Launcher -- Building a Science Museum Classic -  21-Nov-16 -Design News:   Sajjad Haidar - The Jumping Ring or Electromagnetic Ring Launcher experiment is a staple of science museums and physics class rooms.  Here's how to build your own right in your home. __  Gadget Freak

Electromechanical damping stabilizes analog-meter readings -  09/29/05 EDN Design Ideas:  Electronics damps meter-needle swings __ Circuit Design by Alexander Bell, Infosoft International Inc, Rego Park, NY

Electronic Barometer -  Sooner or later the weather hobbyist wants an electronic barometer, the main advantage being that it can be read automatically by a computer, chart recorder, or other data taking system.  Most electronic barometers use some sort of strain gauge transducer to directly convert pressure to voltage and true weather bureau performance can be difficult to achiever __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

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

Electronic Distance Meter -  Simple device for measuring distance while riding bicycle.  The 16-pin Nitron chip interfaces 16x1 line LCD!  __ Designed by Wichit Sirichote

Electronic Electroscope -  An electroscope is the instrument used to detect charged bodies.  Here is an electronic version of the scope that is sensitive and, unlike conventional scopes, indicates the polarity of charge as...__ Electronics Projects for You

Electronic Muscle Stimulation -  This is an electronic muscle stimulator circuit that stimulates nerves of that part of your body where electrodes are attached.  it is useful to relieve headache and muscle pain and revive frozen muscles that impair movement.  its mainly muscle stimulation aid is removing cellulitis and build up you muscles.  Can be used __ Designed by Popescu Marian

Electronic Stethescope Amplifier -  The post explains how to make an electronic stethoscope amplifier circuit for enabling a loud audible reproduction of the heart beats which is being diagnosed.  The article also reveals how the same can be applied within a cellphone through a wireless circuit__ 

Electronic Stethoscope -  Medical and health related electronic circuit diagrams / circuit schematics __ Designed by Aaron Cake

Electronic Stethoscope -  U1a operates as a low-noise microphone preamp.  its gain is only about 3.9 because the high output impedance of the drain of the FET inside the electret microphone causes U1as effective input resistor to be __ Designed by Audioguru

Electronic Thermostat for Fridge -  A thermostat is a standard equipment for sensing temperature of a system and maintaining it at a pre-defined point.  it is a regular feature in air-conditioners, room heaters and refrigerators.  Although...__ Electronics Projects for You

Electronic Watch Dog -  Heres an electronic watch dog for your house that sounds to inform you that somebody is at the gate.  The circuit comprises a transmitter unit and a receiver unit, which are...__ Electronics Projects for You

Electronic Water Alarm -  Aburst water-supply hose of the washing machine, a bathroom tap that you forgot to close, or a broken aquarium wall may turn your house into a pond.  You can avoid this...__ Electronics Projects for You

Electronic Wind Vane with 16-LED Display -  Novel design uses a Gray encoded disc.__ SiliconChip

Electronic-potentiometer system has pushbutton interface -  09/26/02 EDN Design Ideas:  As systems grow smaller, it becomes increasingly attractive to replace mechanical potentiometers with electronic potentiometers, which are smaller and less expensive silicon equivalents.  A common interface for such devices comprises a Chip-Select, increment and, Up/ line.  CS activates the device and, on a rising edge of steps the wiper in a direction that the U/ pin indicates __ Circuit Design by Gene Warzecha and Roger Griswold, Maxim Integrated Products, Sunnyvale, CA

Electroscope - Portable  -  Schematic + info + pictures __ Designed by Lennie Zink

Eliminate thermoelectric EMF in low-ohm measurements -  06/13/02 EDN Design Ideas:  When two different-metal conductors connect together in a loop and one of the junctions is at a higher temperature than the other, an electrical current flows through the loop.  The magnitude of this current depends on the type of metals involved and the temperature differential of the junctions.  When you open such a loop, a thermoelectric voltage appears across the open ends __ Circuit Design by John Wynne, Analog Devices, Limerick, Ireland

EMF Probe Version 2 -  An electromagnetic field probe designed to detect changing electric and magnetic fields.  The probe has switchable gain, a frequency response up to 400kHz and independent audio and meter monitoring.   __ Designed by Andy Collison

EMF Probe with Meter -  This tester is designed to locate stray electromagnetic (EM) fields.  it will easily detect both audio and RF signals up to frequencies of around 100kHz.  Note, however that this circuit is NOT a metal detector, but will detect metal wiring if it conducting ac current.  Frequency response __ Designed by Andy Collison

Emulator Speeds Testing -  09/25/03 EDN Design Ideas:  Designing and testing embedded hardware can be frustrating if you have to rely on somebody else's perhaps-unready firmware to test your hardware.  Often, hardware is ready for testing before debugging and system firm-ware are available from software developers.  Microprocessor emulators are solutions but are often expensive, hard to use, and sometimes inappropriate for use by hardware developers,  __ Circuit Design by Navdhish Gupta, Chicago, IL

Energy Harvesting using a Current Transformer -  Energy harvesting is all the rage these days.  With some modern electronics, information from low power sensors can be sent to a distant data collection point using a low power RF transmitter.  To power these remote sensors, various energy sources can be. . . Circuit by Dave Johnson P.E.-January, 2010

Energy Leak Detector -  High sensitivity, portable temperature comparator; Detects draughts around doors, windows, etc __ Contact Flavio Dellepiane, fladello @ tin.it

Energy Meter -  Electromechanical energy meters have been the standard for metering the electricity since billing began.  But these are now being gradually replaced by electronic digital energy meters.  Presented here is a simple...__ Electronics Projects for You

Energy-Tripped Breaker Trips After a Time Interval that Varies as a Function of Sensed Load Current -  The circuit of this circuit has three distinct parts circuit breaking, current sensing and timing.  The circuit breaking function can be any type of electronically controlled relay or solid state switch, properly sized for voltage and current ratings of the load being protected.  Load current sensing is achieved via __ Linear Technology/Analog Devices App Note, Sep 7th 2011

Engine/Race Computer Board -  The objective of this project is to design a high speed digital engine tachometer.  This requires the design and development of a hardware and software solution to monitor the status of an engine in real time.  in addition, information relating to the overall health and systems of the vehicle can be displayed.   __ Designed by Stephen Manley-smanley @ nyx.net

Enhanced battery "gas gauge" keeps its data through glitches -  01/20/05  EDN Design Ideas:  Texas instruments' BQ2010 battery-"gas-gauge" IC offers a convenient method for recording available charge stored in a nickel-cadmium or nickel-metal-hydride battery.  However, even though plenty of charge remains available, under c __ Circuit Design by Herbert Seidenberg, Costa Mesa, CA

Envelope Tracker Quells Jitter -  07/07/94  EDN Design Ideas:  Fig 1's envelope tracking circuit solves the problem of receiving ac-coupled NRZ data over a coaxial data link.  Because the spectral content of the NRZ data approaches dc (even with alternate frame inversion) , the signal tends to integrate in any ac-coupl __ Circuit Design by Roger C Whipple, Hazeltine Corp, Braintree, MA

Equivalent Series Resistance meter -  Use this handy device to find all those degraded electrolytic capacitors!  __ Designed by Manfred Mornhinweg

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Test Equipment:  #'s - A        B - D        E - G
H - L        M - O        P - S        T - Z


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Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches


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