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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. :

Miniature Pushbutton On/Off Switch -  in many battery powered devices, you would like to turn the circuit on and off by pressing a small pushbutton switch.  One press turns the device on and second press turns it back off.  The flip/flop circuit below uses a minimum number of parts to perform . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Modulated Light Monitor #1 -  This battery powered circuit will work from DC to 500KHz.  it is designed to connect to an oscilloscope to monitor the light level changes and modulated signals. . . Circuit by David A. Johnson P.E.-July, 2006

Modulated Light Receiver Front-End Circuit -  This circuit uses a unique cascode amplifier circuit to convert the current from a PIN photo diode to a current without any feedback network.  it is very stable and very sensitive.  This hobby circuit shown has the potential for a conversion factor of 10 volts per microwatt at 900nm.  I included a simple JFET post-amplifier with a gain of about 20. . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

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

Microcontroller functions as voltmeter -  10-May-07 EDN Design Ideas:  PIC  microcontroller and FETs enable a four-digit voltmeter __ Circuit Design by Noureddine Benabadji, University of Sciences and Technology, Oran, Algeria

Microcontroller multiplexes six digital potentiometers -  05/11/00 EDN Design Ideas:  in Figure 1's circuit, a µC lets you adjust as many as six digital potentiometers.  Like mechanical potentiometers, digital potentiometers can adjust regulator outputs or speaker volumes and act as rheostats.  Available in resistances of 50, 100, and 200 kV, they let you throw away your mechanical potentiometers and the little flat-headed screwdrivers that go with them.   __ Circuit Design by Ted Salazar, Maxim Integrated Products, Sunnyvale, CA

Microcontroller Serial Port Measures Pulse Width -  07/15/10 EDN Design Ideas:  Direct digital synthesys lets you generate a clock at frequencies needed for a standard serial port.   __ Circuit Design by Vishwas Vaidya, Tata Motors Ltd, Pune, India

Microcontroller simplifies battery-state-of-charge measurement -  04/27/06 EDN Design Ideas:  Monitor battery status for renewable energy systems __ Circuit Design by Abel Raynus

Microcontroller, JFET form low-cost, two-digit millivoltmeter -  06/22/06 EDN Design Ideas:  Software subroutines replace hardware A/D converter __ Circuit Design by Noureddine Benabadji, University of Sciences and Technology, Oran, Algeria

Microcontroller-Based Speedometer-Cum-Odometer -  Normally, digital speedometers are found only in luxury cars and high-end motorbikes.  Even if your motorbike has a mechanical speedometer, what will you do when it gets damaged? First, you need...__ Electronics Projects for You

Microcontroller-Based Tachometer -  A tachometer is nothing but a simple electronic digital transducer.  Normally, it is used for measuring the speed of a rotating shaft.  The number of revolutions per minute (rpm) is valuable...__ Electronics Projects for You

Micro-Laser range finder -  Laser range finders are a vital component of high precision targeting engagements.  The precise and accurate range-to-target information is an essential variable in the fire control solution of today’s sophisticated weapons.  This range information is readily provided by the laser range finder, however, current fielded laser range finders are bulky, heavy, difficult to mount onto weapons, eye hazards and very expensive.  The US Army CECOM RDEC NVESD is addressing these laser range finder issues in the development of a Micro-Laser Range Finder (mLRF).  The mLRF is being developed for the soldier, with his special needs a top
priority. __ Designed by Samuel M. Goldwasser

MicroMinimal Thermometer -    NOTE: Must register on this site __ Designed by Published in Elecktor July/Aug, 2010

Microphone Tester -  This circuits is handy for finding an intermittent short or open in a microphone cord or switch.  it produces a week tone in the microphone so that you can flex the cord and operate the switch to find faults.  it won't find an open shield or a short from  __ Designed by Andrew R. Morris

Microprocessor linear potentiometer Deliver echo pulses -  05/12/05 EDN Design Ideas:  Simulate radar and sonar returns with simple circuit __ Circuit Design by Abel Raynus, Armatron International Inc, Malden, MA

MIDITester -  Sometimes when experimenting with different soundcards and MiDI interfaces it is useful to see if there is some data going in MiDI interface.  This can be easily tested with this adapter, which converts the midI signals to visible light pulses.  Just the circuit and plug it to the MiDI output of your computer.  When computer sends any midI data out, you see the LED flashing.  I found this tester very useful in testing homebuilt soundcard MiDI interface. __ Designed by Tomi Engdahl

Millen 90501 Secondary frequency standard -  Schematic Only__ 

Millen 90651A grid-dip meter -  Schematic Only__ 

Millen 90652 solid-state dipper -  Schematic Only__ 

Millen 90662A grid-dip meter -  Schematic Only__ 

Millen 90903 oscilloscope (New version) -  Schematic Only__ 

Millen 90903 oscilloscope (old version) -  Schematic Only__ 

Millen 90912 instrumentation oscilloscope -  Schematic Only__ 

MilliGauss Meter -  The circuit provides an easy yet reliable way to detect the intensity of a.  c. (or e.  l.  f.) fields around the home or workplace.  it is doubly effective because it does not merely detect the electromagnetic radiation emitted by electrical appliances, but the electromagnetic energy actually absorbed by the body.  The circuit in is a standard charge pump __ Designed by Andy Collison

Milliohm Adaptor for Digital Multimeters -  Do you occasionally need to measure very low resistances accurately but don't have access to an expensive benchtop Milliohm Meter or DMM? This low-cost adaptor will let you use almost any DMM to make accurate low-resistance measurements.__ SiliconChip

Milliohm Meter -  Milliohm meter is used to check low resistance of connecting wires.  it can deduce the resistance of thick wires, condition of contacts and the length or quality of wires.  Although the...__ Electronics Projects for You

Milliohm Squawker great at finding shorts & reverse engineering PCBs -  05/23/14  EDN Design Ideas:  This well thought out tool for “listening to” low resistances really speeds troubleshooting & tracing.   __ Circuit Design by Glen Chenier

Mini 3 digit display, an inexpensive digital voltmeter -  We build a simple and inexpensive three digit display.  it's a voltmeter module but it has also general purpose digital iO pins.  You could use it as well to read a digital sensor and display the value.  it can be freely programmed, calibrated and even be programmed with a non linear formula.  it's a display where you can define the relation between the measured value and the displayed number.   __ Designed by Guido Socher

Mini oscilloscope based on PIC18F4620 & standard 16x2 text LCD display Module -  The idea of this circuit is use text LCD programmable characters to display a signal.  A function generator was used to generate the signal we can see in the the videoclip __ Designed by Bruno Gavand

Mini Tester -  This is a very useful circuit which can be used for testing electronic component.  Like multimeter one can use this circuit for :- continuity testing, resistor testing, capacitor testing and diode testing.  in this circuit LED glows only when probes L1 and L2 are short-circuited or has a path for the current to flow.  This fact will be used to test components. __ ` Sigmatone

Miniature Pushbutton On/Off Switch -  in many battery powered devices, you would like to turn the circuit on and off by pressing a small pushbutton switch.  One press turns the device on and second press turns it back off.  The flip/flop circuit below uses a minimum number of parts to perform . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Miniature SWR / RF power meter -  After building my Z-match tuner, I wanted to design a circuit board for a Stockton type swr/pwr meter that I could reproduce easily and see how small I could make it.  The result is in the above picture.  it is a board that measures a scant 1" x 1.5" and is made from common single sided copper clad board.  I drew the lines on the board with a pencil, and then used a Dremel tool and an abrasive wheel to cut the traces in the copper that isolates the individual pads that the components solder to.  The circuit is a variant of the Stockton type of bridge used in many commercial swr/pwr meters and kits these days.   __ Designed by KC8AON's QRP PROJECTS

Minimize Noise In Power-Supply Measurements -  07/28/11  EDN Design Ideas:  Eliminating excess noise from an oscilloscope probe yields better measurements.   __ Circuit Design by John Lo Giudice, STMicroelectronics, Schaumburg, IL

Minimum Mass Waveform Capture & Display -  The result was a project that includes a waveform capture circuit, a graphic LCD (Liquid Crystal Display) and a control panel with LED indicators.  The details of the Graphic LCD display unit, composed of the LCD module, a serial interface, and bias supply were published earlier on this site,  __ Designed by Dick Cappels

Miniscope-Simple Circuit all-valve 1-Inch CRT oscilloscope -  This beautiful homemade oscilloscope is the craftmanship of the late Len Hall G3iGI and was kindly given to me by Graham Firth G3MFJ at the 2008 G-QRP-club mini-convention.  Graham has seen my own 1-inch oscilloscope project (also pictured, far right) and knew I'dbe interested in it!  Another similar project (right) is by Andy G4OEP.. __ Designed by Hans Summers

Missing Pulse Detector Basic -  This circuit is a one-shot that is continually retriggered by incoming pulses.   __ Designed by Tony van Roon  VA3AVR

Missing Pulse Detector with 555 IC -  Missing pulse detector will receive a source of repetitive pulse in normal condition.  The output of this detector circuit will be inactive for normal condition (output pin 3 of  555  IC will be high, turning off the LED indication).__ 

Missing-codes tester checks 16-bit ADC in 7 sec -  06/10/99 EDN Design Ideas:  As the resolution of ADCs increases from 12 to 16 bits and higher, the difficulty in testing the"nomissing-codes"specification grows proportionately.  To fully guarantee no missing codes for a 16-bit ADC requires testing all 2 16-1 possible output __ Circuit Design by Mark A Shill, Burr-Brown Corp, Tucson, AZ

Model 2030 XRAY Monitor instruction manual including Schematics -  Medical and health related electronic circuit diagrams / circuit schematics__ 

Model Aeroplane Navigation Strobe/Battery Level Indicator  -  if you are interested in model aeroplanes and have the capital, a radio controlled electric park flyer is a must have.  An RC aeroplane under 400 grams floats around like the rubber models of my youth and contact with the ground doesn't seems to involve that sickening crunch __ Contact r dot p @ webone.com.au

Model fixed-point DSP arithmetic in C -  03/18/99 EDN Design Ideas:  NOTE:     Page includes several designs.  Scroll to find this one.  You can run initial high-level simulations of custom numerical algorithms, such as digital filters, using floating-point numbers in an environment such as C or Matlab.  Unfortunately, you won't see include fixed-point effects, such as truncation due to limited precision and register overflow, until you use a Hardware Design Language (HDL) , such as Verilog or VHDL.  However, a technique that models these effects in C—the function "bit_limit" in Listing 1—provide as faster execution and better portability than HDLs and allows early exploration of the trade-off between bus width and performance.   __ Circuit Design by Roger Maher, SSL Ltd, Dublin, Ireland

Model Rocket Altimeter -  Circuit Only__ 

Modifications for CDV700 Geiger Counter -  This project involves making several modification to an early 1960s era Victoreen CDV700 or CDV600-6B geiger counter.  These counters are available on E-Bay for around $50 to $100.  The modifications use modern electronic parts to improve the counter's stability, extend the run time, and add a solar recharging capability.   __ Designed by Forrest Cook

Modified Scope Probe Tests Surface Mount Assemblies -  09/25/97 EDN Design Ideas:  The small sizes and pad areas of surface-mount components make them difficult to probe.  Typically, when you use an oscilloscope probe, it is difficult to keep the probe tip and ground bayonet from slipping off the pad areas of the surface-mount devices.  The modified oscilloscope probe __ Circuit Design by Robert Buono, Mahwah, NJ

Modify a CDV-715 Survey Meter for High Sensitivity -  This project endeavors to modify an ion chamber style radiation meter, the CDV-715, so that it has useful sensitivity, taking advantage of the internal ion chamber, high value resistor, and nice packaging.  The new circuit increases the electrical gain by 1000, converting the scales from R to milli-R.  I decided to abandon virtually all of the existing electronics for several reasons.  The chamber current is converted into a voltage by switched resistors but the ceramic switch will simply leak too much; it can only be used for range switching after amplification.  There is no need for 1.5 volts since there will be no filament to heat so the inverter that converts 1.5 volts to 50 volts and 10 volts will be unnecessary.  A 9 volt battery will power the electronics and a unique version of the Cockcroft-Walton voltage multiplier will generate the 50 volts for ion chamber bias.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Modulated Light Monitor #1 -  This battery powered circuit will work from DC to 500KHz.  it is designed to connect to an oscilloscope to monitor the light level changes and modulated signals. . . Circuit by David A. Johnson P.E.-July, 2006

Modulated Light Receiver Front-End Circuit -  This circuit uses a unique cascode amplifier circuit to convert the current from a PIN photo diode to a current without any feedback network.  it is very stable and very sensitive.  This hobby circuit shown has the potential for a conversion factor of 10 volts per microwatt at 900nm.  I included a simple JFET post-amplifier with a gain of about 20. . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Modulation Monitor -  Very simple and useful circuit used to monitor on air transmission of your low power amplitude modulated transmitter.  __ 

Moisture Monitor for Plants -  Over-watering and under-watering both are harmful for plants.  Roots need air as well as water.  if the soil is constantly saturated, air cannot reach the roots and they suffocate.  Also, excess...__ Electronics Projects for You

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

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

 


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