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Tester or Measurement (Instrument) Circuits

Test Equipment:  #'s - A        B - D        E - G
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Last Updated: October 24, 2017 02:55 PM
Circuits Designed by Dave Johnson, P.E. :

Improved Solar Path Light -  The circuit below was designed to replace the guts of an existing path light assembly with one which has a much better performance.  I suggest using a quality 10 cell solar panel with at least a 4 square inch area.  Buy a panel with solar panels that fills . . . Hobby Circuit designed by David Johnson P.E.-March, 2011

Indicate Electrical Current with this Circuit -  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 . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2005

Indicates 120 VAC or 240 VAC -  Two LEDs indicate if a power line has 120vac or 240vac voltage on it . . . Hobby Circuit designed by David A. Johnson P.E.-January, 2007

Indicates when it is Time to Dust -  I have used the circuit below for many different applications, which require ultra low power drain.  it uses a single CA4013 flip/flop.  One section forms a pulse generator.  The generator produces 100uS pulses at a rate of about 1 per secondCircuit Solution by David Johnson P.E.-May, 2006

Indicates when it is Time to Dust -  I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work. . . Circuit by David Johnson P.E.-June, 2000

Indicator for Acceptable Voltage -  I have used this circuit many times in custom test fixtures where a simple go-no go indication was needed.  The circuit can also be used to adjust a particular voltage be within specific high or low limits.  The three LEDs will indicate if the voltage is . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2002

Indicator for Bad Light Bulb -  This request came from a Discover Circuits visitor.  He wanted to turn on a LED indicator light whenever a circuit detected a burned out tail/brake light on a car or truck.  The circuit shown below uses a transistor switch, to detect current flowing through a low value resistor . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2006

Inductor Self-Resonance Tester -  if you want to know what the self-resonance frequency is of an inductor, this circuit will help.  it adds only a few picofarads of parallel capacitance to the inductor under test.  With the aid of an oscilloscope and a signal generator this circuit will allow you to measure resonant frequencies from kilohertz to over 10 megahertz. . . Circuit by David Johnson P.E.-June, 2000

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Implement Photovoltaic-Module Simulator -  04/07/11  EDN Design Ideas:  Use combinations of diodes to simulate photovoltaic cells.  Electronics engineers often use photovoltaic-module simulators to test dc/dc-power converters, inverters, or MPPT (maximum-power-point-tracking) -control techniques.  The use of these simulators lets you work in the laboratory with predefined photovoltaic conditions, thus avoiding the drawbacks of real photovoltaic modules.  Various commercial simulators are available, but they are often expensive.   __ Circuit Design by José M Blanes and Ausiŕs Garrigós, University Miguel Hernández, Elche, Spain

Implementing a Smoke Detector with the MSP430F2012 -  Smoke Detectors are designed for 3 basic types of system implementations; Standalone, Wireless Connectivity, and Fixed/Wired Connectivity, the first two being battery powered implementations.  Smoke Detectors have 3 main functional blocks; The Sensor and Signal Chain, Processor, and the Communication interface.  Where the processor and communications interface typically are not needed in your very basic standalone detectors __ Designed by Texas Instruments App Notes, 18-Sep-06

Improve On First-Event Detection -  08/16/01  EDN Design Ideas:  The circuits in Figure 1 and Figure 2 exhibit certain advantages over the circuit shown in the Design ideas - in __ Circuit Design by Lawrence Arendt, Oak Bluff, MN, Canada

Improve On Temperature Measurement -  05/02/02  EDN Design Ideas:  When current pulses with a stable iHiGH/iLOW ratio modulate a semiconductor junction, the ensuing voltage difference (for example, ΔVBE for a bipolar transistor] is a linear function of the absolute (Kelvin] temperature, T.  You can us __ Circuit Design by Alexander Bell, Infosoft International Inc, Rego Park, NY

Improved current Monitor Delivers proportional-voltage output -  01/19/06 EDN Design Ideas:  New, improved circuit delivers an accurate linear-voltage output proportional to current in primary winding __ Circuit Design by Susanne Nell, Breitenfurt, Austria

Improved Kelvin contacts boost current-sensing accuracy by an order of magnitude -  02/17/05 EDN Design Ideas:  Many power-supply designs rely on accurately sensing the voltage across a current-sense element.  Multiphase regulators use the sense voltage to force current sharing among phases, and single-phase regulators to control the current-limit setpoint.  As internal complexity and clock speeds increase, processors impose narrower operating margins for power-supply voltages and currents, which in turn m __ Circuit Design by Craig Varga, National Semiconductor Corp, Phoenix, AZ

Improved Solar Path Light -  The circuit below was designed to replace the guts of an existing path light assembly with one which has a much better performance.  I suggest using a quality 10 cell solar panel with at least a 4 square inch area.  Buy a panel with solar panels that fills . . . Hobby Circuit designed by David Johnson P.E.-March, 2011

Improved Transistor Circuit for the Ionization Chamber -  These "ion chambers" are nothing more than a bare wire stuck through a hole into a metal can!  No special gas or sealing is required.  For best performance it is probably a good idea to add a desiccant to the inside of the can to keep the humidity low. (I didn't!) Build one; its really simple!  __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Improved two-tone, third order testing -  Application Note__ MiniCircuits.com

In-circuit electrolytic capacitor checker -  The circuit looks very simple but the two components in the "font end" provide a very accurate discharge-time.   These two components are the 220R and the voltage-reference (made up of the two green LEDs).  A green LED produces a characteristic voltage across it of 1.9v. __ Designed by Colin Mitchell, Talking Electronics

In-circuit PROM tester -  EDN Design Ideas:  06/09/2016    Maintaining old tech takes some resourcefulness __ Circuit Design by Barry Davies

Increasing Regulator Current -  An outboard pass transistor used to increase the current output of a voltage regulator IC .   __ Designed by Andy Collison

Indicate Electrical Current with this Circuit -  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 . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2005

Indicate Health of Lithium-Ion Batteries -  05/14/09  EDN Design Ideas:  A simple inexpensive circuit quickly indicates a battery pack's health __ Circuit Design by Fritz Weld, Friedberg, Germany

Indicates 120 VAC or 240 VAC -  Two LEDs indicate if a power line has 120vac or 240vac voltage on it . . . Hobby Circuit designed by David A. Johnson P.E.-January, 2007

Indicates a Low battery -  02/03/14 - EDN Design Ideas:  it may seem a bit counterintuitive to power on an LED when a battery is already low, but this Design idea does it with aplomb __ Circuit Design by James Wood

Indicates when it is Time to Dust -  I have used the circuit below for many different applications, which require ultra low power drain.  it uses a single CA4013 flip/flop.  One section forms a pulse generator.  The generator produces 100uS pulses at a rate of about 1 per secondCircuit Solution by David Johnson P.E.-May, 2006

Indicates when it is Time to Dust -  I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work. . . Circuit by David Johnson P.E.-June, 2000

Indicator features expanded scale -  02/21/02  EDN Design Ideas:  Test equipment for a production line should be user-friendly (read "idiot-proof"] and should offer minimal test time.  in many cases, the test fixture must give an operator only one answerpass or fail.  Usually, two indicators assum __ Circuit Design by Abel Raynus, Armatron International, Melrose, MA

Indicator for Acceptable Voltage -  I have used this circuit many times in custom test fixtures where a simple go-no go indication was needed.  The circuit can also be used to adjust a particular voltage be within specific high or low limits.  The three LEDs will indicate if the voltage is . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2002

Indicator for Bad Light Bulb -  This request came from a Discover Circuits visitor.  He wanted to turn on a LED indicator light whenever a circuit detected a burned out tail/brake light on a car or truck.  The circuit shown below uses a transistor switch, to detect current flowing through a low value resistor . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2006

Inductance meter -  Determination of the resonance frequency of a parallel LC network is one of the most important measuring problems in the ham shack.  Not unjustly the commonly used dip meter is nicknamed sounding-rod of the radio amateur.  A more elegant method for measuring the resonance frequency is __ Designed by Aren van Waarde

Inductance meter  -  Schematic Only__ 

Inductance meter adapter -  The following circuit enables me to measure inductance of the inductor labeled LX which is the inductance to be measured.  The o/p of the circuit is a TTL square wave whose frequency relates.  By Tosin OsanyintuyI (TAFRIC A)  __ Contact IQ Technologies

Inductance meter for RF Inductors  -  needed a way to measure hand-wound RF inductors in my second lab, and since I would only be doing this occasionally, I didn't need anything fancy, and since once a friend finishes his AT90S1200-based design, I plan to make one myself, I figured I'duse this for less than a year, so I didn't want to invest __ Designed by Dick Cappels

Inductance tester uses few components -  04/12/07  EDN Design Ideas:  This circuit plus a frequency counter or oscilloscope measures unmarked inductors __ Circuit Design by Al Dutcher, Consulting Engineer, Paulsboro, NJ

Induction receiver for tracing wiring behind walls, hearing lightning & other electric discharges -  The induction receiver shown below is very sensitive and can serve a variety of purposes.  it is excellent for tracing wiring behind walls, receiving audio from an induction transmitter, hearing lightning and other electric discharges, and __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Inductive Meter Adapter -  Measure inductance using a frequency counter__ 

Inductive sensing with left-handed antenna for biomedical applications -  05/15/14 EDN Design Ideas:  Could an inductive sensor help assay biological and other substances? A left-handed (LH) antenna based biosensor is developed to investigate the near-field electromagnetic interaction between antenna and sample with different dielectric properties.  These dielectric properties can be determined by analyzing the electromagnetic coupling between the antenna and the test samples without labeling or chemical reaction.  it has the advantages of real-time detection, small feature size, reduced sample volume, and minor environmental disturbance.  Such an antenna sensor can be effectively used to measure both liquid and solid biological samples.   __ Circuit Design by Chii-Wann Lin

Inductively sense aircraft engine valve position -  04/25/14 EDN Design Ideas:  Aircraft engine designers are conservative by nature, but here's a way to improve performance anyway.  This design uses an inductor to sense the position of a valve on an aircraft engine as a way to get camshaft position information.  Knowing the camshaft position along with the crankshaft position allows fuel injection while the intake valve is open and the use of individual coils for each cylinder.   __ Circuit Design by Angus McCamant

Inductively sense workpieces of any material -  05/16/14 EDN Design Ideas:  Create an inductive switch using the LDC1000 to replace mechanical switches in dirty environments.  The problem originally undertaken was to sense the presence and position of nonmetallic objects in a gritty environment – such as a paper mill or woodworking operation – that requires accurate workpiece sensing for certain cutting and routing operations.  Microswitches are fragile and clog easily.   __ Circuit Design by Fred Rupinski

Inductor Self-Resonance Tester -  if you want to know what the self-resonance frequency is of an inductor, this circuit will help.  it adds only a few picofarads of parallel capacitance to the inductor under test.  With the aid of an oscilloscope and a signal generator this circuit will allow you to measure resonant frequencies from kilohertz to over 10 megahertz. . . Circuit by David Johnson P.E.-June, 2000

Industrial Sensor 4mA to 20mA Current Loop Power Tap -  The LTC3105 is a high efficiency step-up DC/DC converter that can operate from input voltages as low as 225mV.  A 250mV start-up capability and integrated maximum power point controller (MPPC) enable operation directly from low voltage, high impedance alternative power sources such as photovoltaic cells, TEGs (thermoelectric __ Linear Technology/Analog Devices App Note, Mar 16th 2011

Industrial-Grade Digital Potentiometer -  09/20/01  EDN Design Ideas:  Both ac and dc motors in modern industrial systems often receive their control from PLCs (programmable-logic controllers] in a control room safely away from the process.  if an operator must manually set the motor speed while observi __ Circuit Design by Phill Leyva, Maxim Integrated Products, Sunnyvale, CA

Inexpensive APRS Weather Station -  There are two kits you need to get for this weather station.  The first is the outdoor sensor.  it costs about $80 and can be bought online from the AAG.  http://www.  aag.  com.  mxThis kit provides the sensor unit (some assembly required) and an interface that allows you to hook it up to your __ Designed by Will Beals

Inexpensive peak Detector requires few components -  07/07/05  EDN Design Ideas:  All-analog circuit needs no rectifiers __ Circuit Design by Anthony H Smith, Scitech, Bedfordshire, England

Inexpensive Relays Form Digital Potentiometer -  03/13/98 EDN Design Ideas:  NOTE:  File contains many circuits, please scroll to find this one.  Build a digitally controlable isolated potentiometer that can tolerate voltages up to 60-Volt dc __ Circuit Design by Robert Perrin, Z-World, Davis, CA

Inexpensive Remote Watering System -  This remotely controlled watering system is both inexpensive and easy to expand.  it is designed to operate in conjunction with a conventional watering timer and allows remote switching between nine zones.  The prototype is used in a bore system, where a deep-well pump must be started and kept running while zones are being changed.  This is necessary to minimise cycling and results in maximum pump life.  A standard portable telephone is used as the transmitter and receiver__ Learning Electronics

Infrared beam barrier / proximity Detector -  This circuit can be used as an infrared beam barrier as well as a proximity detector.  The circuit uses the very popular Sharp IR module (Vishay module can also be used).  The pin nos.  shown in the circuit are for the Sharp & Vishay modules.  For other modules please refer to their respective datasheets.  The receiver consists of a 555 timer IC working as an oscillator at __ Contact http://www.tronicszone.com

Infrared Detector -  This circuit is a simple IR detector for testing IR remote controllers.  The circuit is based on one phototransistor which receives the IR beam.  The NPN transistor works as an amplifier which feeds current to the led.  When this circuit detects IR or light, the LED is on.  So you need to shield the phototransistor from ambient light if you don't want to do your tests in the dark.  The best way __ Designed by Tomi Engdahl

Infrared Detector -  The circuit of manufacture appears in form.  sensory is a passage of silicon with relatively big surface.  This passage when it is not litted up by infra red light has very big resistance of order of Mohm.  this resistance is reversely proportional at approach of brightness.  The type of passage is not critical, in the place can enter anyone.  The resistance of passage __ Designed by Soylis Papanastasiou

Infrared Detector -  This circuit is a simple IR detector for testing IR remote controllers.  The circuit is based on one phototransistor which receives the IR beam.  The NPN transistor works as an amplifier which feeds current to the led.  When this circuit detects IR or light, the LED is on.  So you need to shield the phototransistor from ambient light if you don't want to do your tests in the dark.  The best way __ Designed by Lennie Zink

Infrared Flame Sensor Switch -  the infrared detector switch is a very sensitive circuit that can be use to detect the presence of a flame, match, or a heat source, such as an iron or soldering iron.  up to 3 feet away an then activate a relay.  the heart of the infrared flame detector circuit is two tiny thermistor, as shown in figure 1.   __ Designed by Edy Jankovic

Infrared gate 2 -  This is an infrared gate with two sensors planned to use in the wall in the way behind a door.  it can be applied in a toilet to keep track of that someone is inside exceeding a certain amount of time.  After that time elapsed, the circuit triggers the digital output wich can turn on a ventillator.  The time period the output is turned on can be separately controlled by a second timer. __ Designed by Peter Jakab

Infra-red Level Detector -  Useful for liquids level detection and proximity devices; Up to 50 cm.  range, optional relay operation __ Contact Flavio Dellepiane, fladello @ tin.it

Got Designs?
Please eMail
if you want me to link to and/or post your original design.  Thanks.

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