Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com has links to 45,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.

HOME Schematics Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches
Welcome to DiscoverCircuits.com - online since 2002

See Media Kit for
Advertising Opportunities

Attention Designers:  Please alert us by eMail if we have linked to sites
where your original material has been copied without your permission.
We will change to the LINK to your site.  
Thank you.

 


Tester or Measurement (Instrument) Circuits

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


Last Updated: October 24, 2017 02:55 PM
Circuits Designed by Dave Johnson, P.E. :

Isolated AC Current Monitor -  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. . . Circuit by Dave Johnson P.E.-July, 2006

Isolation Transformer Circuits -  A while back I needed to test a circuit at 240vac.  Since I needed to safely test the circuit using my oscilloscope, I needed the 240vac to be fully isolated from the power line.  So, to step up the voltage, I bought a small isolation transformer from Digikey. . . Circuit by David A. Johnson P.E.-May, 2011

It's Time to Dust Indicator -  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 . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Consulting Services include:
Applications Engineering   --    Design & Development
Electronic Circuit Design   --   Custom Test Fixtures

Call 806-368-7747


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

Isolated Current & Voltage Monitor -  The LTC4151-1/LTC4151-2 split the SDA line into SDAI (input) and SDAO (LTC4151-1 inverted output) or SDAO (LTC4151-2 output) for convenience of opto-coupling with a host controller that sits at a different ground level.  When using opto-isolators with the LTC4151-1, connect the SDAI to the output of the incoming opto-coupler __ Linear Technology/Analog Devices App Note, Mar 31, 2010

Isolated current sensing with ∑-∆ optoisolators -  EDN Design Ideas:  06/12/2014    Sigma-delta optocouplers make for accurate isolated sensing, and can trade off speed for ENOB.    __ Circuit Design by Avago Tech Note

Isolated Low Power pH Monitor with Temperature Compensation  -  Follow the instructions contained in the Readme file for installing and using the evaluation software.  Setup The CN0326 evaluation kit includes self-installing software on a CD.  The software is compatible with Windows® XP (SP2) and Vista (32-bit and 64-bit).  When the evaluation system is successfully detected by the PC, the EVAL-CN0326-PMDZ circuit board can now be evaluated using the software shown in Figure 9.  __ Analog Devices from the Lab

Isolated Monitors AC line -  5-Jul-07 EDN Design Ideas:  A simple circuit develops a square wave whose pulse width is proportional to the mains-voltage level __ Circuit Design by David Williams, Millington, MI

Isolated oscilloscope probe -  Working on live telephone circuits can be a problem.   You just can't connect a normal scope probe to the circuit while it is tied to the phone line. __ Designed by Luhan Monat - Mesa Arizona

Isolated Power Line Monitor with 0.5% Accuracy Over 90VAC to 130VAC Input -  This circuits AC power line monitor has 0.5% accuracy over a sensed 90VAC to 130VAC input and provides a safe, fully isolated output.  RMS conversion provides accurate reporting of AC line voltage regardless of waveform distortion, which is common.  __ Linear Technology/Analog Devices App Note, Mar 31, 2010

Isolated Probe -  PIC  Project  Working on live telephone circuits can be a problem.  You just can't connect a normal scope probe to the circuit while it is tied to the phone line __ Designed by Luhan Monat - Mesa Arizona

Isolation Transformer Circuits -  A while back I needed to test a circuit at 240vac.  Since I needed to safely test the circuit using my oscilloscope, I needed the 240vac to be fully isolated from the power line.  So, to step up the voltage, I bought a small isolation transformer from Digikey. . . Circuit by David A. Johnson P.E.-May, 2011

Isolator/Circulator (Reprint courtesy of RF Design Magazine) uses ICs. Here's an external link to a reader's version: http://www.neazoi.com/circulator/index.htm -  The ferrite circulator/isolator is an amazing and important tool for the microwave engineer.  Unfortunately, for frequencies below several hundred megahertz, the size of the magnets and ferrite becomes unworkable and the cost skyrockets.  With the advent of remarkably fast op-amps, it has become practical to construct a low power equivalent to the circulator that works all the way down to DC and exhibits superb reverse isolation and impedance characteristics to frequencies above 100 MHz. (Reprint courtesy of RF Design Magazine) Here's the link: http://www.neazoi.com/circulator/index.htm __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

It's Time to Dust Indicator -  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 . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Jelly Bean Function Generator -  This function generator was originally designed to mount on top of the PPMScope Oscilloscope as a second board.  I later trimmed the sides of the PCB to reduce it's size.  it generates sine waves, square waves, and triangle waves.  You can adjust the frequency, amplitude, and offset.  it only utilizes a comparator, a few op amps, transistors, and passive components.  I call it the "Jelly Bean Function Generator" because it is doesn't utilize a function generator IC .  The design was inspired by a college project, but it operates fairly well for a simple low cost function generator __ Designed by Johnathan Weaver

Jogging Timer -  3V Battery powered; Beeps after a fixed minutes delay __ Contact Flavio Dellepiane, fladello @ tin.it

K2LMG/W5EUT 1-Wire Barometer--5/10 Volt Design vrs 2 -  This article describes details for constructing a 1-Wire Barometer which will work on a Dallas Semiconductor Corporation 1-Wire network.  it differs from the popular Version 1.1a in that it has more than twice the resolution. __ Designed by David W. Bray

K2LMG/W5EUT 1-Wire Barometer--5/10 Volt Design Vrs 3 -  This article describes details for constructing a 1-Wire Barometer which will work on a Dallas Semiconductor Corporation 1-Wire network.  This design differs from the popular Version 1.1a in that it has more than twice the resolution. __ Designed by David W. Bray

KC7783R PIR Module -  Find out more about the economical and easy to use KC7783R PiR motion sensor module.   __ Designed by REUK-Renewable Energy UK website

KD1JV Digital SWR / Power Meter -  This small, light weight digital SWR and power meter uses an Atmel AVR "Butterfly" demo board and a "Stockton" type directional coupler.  it is built into a "Whitmans Sampler" candy tin.  The display board is mounted to the lid of the tin, so the cover can be closed to protect the display when the unit is not in use or is in transport.  This makes it an idea meter to use when traveling or in the field. __ Designed by Steven Weber, KD1JV

Keys Finder -  The ear and mouth of the circuit is a piezoelectric buzzer.  Fizzling in a frequency of 34 KHz produced sound waves that piezoelectric buzzer converts them to an oscillation.  This oscillation passes thought C1 and thought inverters N1N3.  The inverters along with R1 and R2, compose an amplifier with gain 400 ! .  The C8 and C9 stabilize and reduce the signal's level.  __ 

Lab-Standard 16-Bit Digital Potentiometer -  No, this is not some kind of fancy digital volume control for hifI systems.  instead, it's a low-cost digital programmable voltage divider.  it's used to provide an accurate adjustable output from a precision voltage reference for meter calibration and other tasks.__ SiliconChip

LabVIEW real-time seismic alert system -  06/30/14  EDN Design Ideas:  This Design idea describes a real-time seismic alert system, which acquires seismic alert data from the European Mediterranean Seismological Center (EMSC) public web page using the “Data Socket connectivity” library in LabViEW as part of a virtual instrument.   The Real Time Earthquake information (RTEi) services operate with the support of the Laboratory for Detection and Geophysics seismic group (LDG) by compiling real time parametric data received by email and provided by 66 seismological networks.  EMSC provide as several services in the field of rapid information on the European-Mediterranean seismicity and significant earthquakes worldwide. __ Circuit Design by Janani Jayapandian & nandhini Jayapandian

LAN cable tester -  Here's a very simple, but practical circuit, which is used to check the type of LAN cables (straight or cross) as well as possible faults.  So we use a unit that has 8 outputs, each one of which produces a pulse successively. __ Designed by Vassilis Stergiopoulos ©

Large Cookie Tin Ion Chamber -  Here is a truly simple experimenter's chamber made from an ordinary cookie tin.  This experimenter's chamber is made from a 4" (10 cm) diameter, 5.5" (14 cm) tall tin with a tight-fitting lid.  A 5-way binding post is mounted in the center of the can and a 4" (10 cm) wire is suspended from the post inside the can.  The wire length is short enough to insure that it doesn't touch the lid.  Another all-metal binding post and pin are installed in the bottom of the can, and a sheet of gray insulating plastic is glued into place to keep hastily constructed experiments from contacting the can.  The electrometer circuitry will be extremely sensitive to stray electric fields, so a shield is mandatory.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Large Inductor Quick Tester -  Battery Topper:  The Large inductor Quick Tester is basically an LC oscillator that makes determining the value of large inductors quick and easy.  in the spirit of "Battery Toppers", the circuit requires no power switch and may be mounted directly on top of a lantern battery which provides a nice, heavy base.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Laser Burst Light Detector -  This circuit was originally designed to detect weak flashed of laser light bounced off of a fabric video projection screen.  it was used as part of a firearm training system.  it generates a 100mS output pulse whenever it detects a 3ms to 5ms laser burst, modulated at 40KHz.  it is very sensitive and could be modified for long range laser communications. . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

Laser Diode Tester -  This circuit can either be used to test laser diodes or as a general purpose modulated light source.  The circuit has an adjustable diode threshold current and an adjustable modulation frequency.  The frequency can be adjusted from below 30KHz to above 50MH. . . Circuit by David A. Johnson P.E.-March, 1999

Laser Light Show -  A programmable laser light show that allows the user to specify the pattern displayed via three motor speeds and the length of time that this pattern is held. __ Designed by Matt Melynk and Josh Silbermann

Laser Power Meter -  The construction of a simple and inexpensive laser power meter is described.  The laser power is monitored using a calorimeter sensor which is based on the use of commercial platinum resistors.  in this design, the use of volume absorbing glass enables the meter to withstand peak power densities in the region of 100 MW cm-' and average powers in excess of 10 W at 1.06 pm __ Designed by A. I. Ferguson

Laser/LED Light Output Intensity Meter -  This circuit uses a large 1cm X 1cm silicon PIN photo diode and a transimpedance amplifier to measure the light power output of infrared and visible LEDs and laser diodes.  it can be modified to produce almost any milliwatts to volts scale factor.  it can be. . . Circuit by David A. Johnson P.E.-July, 2000

Latching Continuity Tester -  A continuity tester is a must on every service bench for testing cables, pc-boards, switches, motors, plugs, jacks, relays, and many other kinds of components.  But there are times when a simple continuity test (or your multi-meter) doesn't tell the whole story.  For example, vibration-induced problems in automobile wiring can be extremely difficult to detect because a short or open is not maintained long enough for a non-latching tester to respond __ Designed by Tony van Roon  VA3AVR

Latching Continuity Tester 1 -  This Latching Continuity Tester can help you locate those difficult-to-find intermittent short and opens that other testers always seem to miss.  it has been part of my workbench for many years and performs superb.  I have solved many intermittend problem with this highly flexible unit __ Contact IQ Technologies

Latching continuity tester using 4093 -  This is a variation on the astable multivibrator.  Circuit was recently developed to test for N-MOSFETs (the power kind e.g irf830) __ 

Latching Regulator Prevents Deep Discharge -  03/16/95 EDN Design Ideas:  To avoid a deep discharge that can shorten or destroy a rechargeable battery's life, you need to remove the load at the point of complete discharge.  Because a battery's terminal voltage recovers after load removal, you can't simply disconnect the load when the voltage dips below a threshold and reconnect it when the voltage returns above that threshold __ Circuit Design by Doug Vargha, Maxim Integrated Products, Sunnyvale, CA

LC Determination by Resonant Frequency Measurement ATtiny2313, AT90S2313 -  A well known L/C measurement circuit is pressed into service to make a bare bones measurement circuit.   __ Designed by Dick Cappels

LC filter Design on-line calculator -  This is an interactive design package for designing analogue (i.  e.  hardware) filters made of inductors and capacitors (Ls and Cs).  Fill in the form and press the ``Submit'' button, and a filter will be designed for you.   __ Designed by Tony Fisher

LC Meter Based on the AVR MicroController -  Calculates and displays L and C from oscillation frequency using reference components.  This instrument requires two precision components: A precision capacitor and a precision inductor.  You only need to start with one precision component, either the reference capacitor or the reference inductor, and using this meter, you can select or adjust the other precision component.  in my case, I used a pretty high accuracy BK Precision inductance/capacitance meter and sorted through piles of inductors and capacitors to find those that had the lowest error.  I then used those parts, __ 

LC meter with LCD display for readout -  This project will prove to be a worthwhile addition to my equipment and was fun to build.  What can I say? I love electronics.  What i'm finding interesting at the moment is the number of projects using PIC  chips that give results approaching lab quality performance at much less than lab quality prices.  This is an interesting time in electronics for the hobbyist.   __ Designed by vk5zvs

LC-& Q-meters-Radiometer MM1f multimeter -  Modification in particular to achieve better reading between 20nH-2µH coil inductance.  Note the series coil, it is the secret why it is possible to measure inductance values down towards zero. (Since it is a gif file it prints better than it seems on the screen).  it is usually no problem __ Designed by Jan-Martin Nřding

LCD Panel Meter -  How to make a volt and amp meter for your battery bank.  Click Here__ 

LCD thermometer -  in this page, I introduce the LCD thermometer which is sold by "AkizukI DenshI Tsusho".  At this thermometer, the IC thermo sensor (S8100) or the diode (1S1588) is used as the thermo sensor.  When using the IC thermo sensor, the thermometry to +100°C from -40°C is possible.  Also, when using the diode, the measurement to +150°C from -20°C is possible.  Both sensors are contained in the kit.   __ Designed by Seiichi Inoue

LCD thermometer using PIC16F871 -  Build your own temperature meter for fun.  This project uses the Microchip TC77 digital temperature sensor,  a PIC 16F871 microcontroller and a 7-segment 3˝ digit LCD.  You can study the source code on how to drive an LCD display.   __ Designed by Peter Jakab

LDR & LED Smoke Detector -  Smoke detectors are generally used in advanced alarm systems.  Most of this professional devices use gas-detectors, ionization rooms or radioactive elements as sensors.  in this circuit we are not using any of this complicated components.  instead of these, we are using two LDRs and one LED.  LM1801 special-purpose IC , which is designed especially for smoke detectors, provides us building this circuit by using the minimum number of components.  it includes one internal zener supply, two reference voltage outputs, one voltage comperator, fixing diodes and one 500mA output transistor.  __ 

Lead-Acid Battery Low Voltage Indicator -  Lead-acid batteries should not be discharged below a certain voltage.  Discharging a cell below about 1.8v and can often damage it, which will result in a lower amp-hour capacity.  Large battery banks are critical in off-grid energy storage systems.  One. . . Circuit by David A. Johnson P.E.-July, 2006

Lead-Acid Battery Monitor -  This mini-project came about from building a garden shed.  I decided to re-purpose an old UPS battery along with some spare halogen downlighters for illumination.  But as I researched lead-acid technology, I decided that I needed something rather more sophisticated than a simple switch if I wanted the batteries to survive __ Designed by Mark Hennessy

Leakage & Continuity Tester -  Here is a simple, chargeable leakage and continuity tester that can be operated in two modes: normal mode and gain mode.  The gain mode is especially useful for detecting small leakages...__ Electronics Projects for You

LED 12 Volt Lead Acid Battery Meter -  in the circuit above, a quad voltage comparator (LM339) is used as a simple bar graph meter to indicate the charge condition of a 12 volt, lead acid battery.  A 5 volt reference voltage is connected__ 

LED AM meter -  Measures current up to 10A with selected 100mA, 10mA and 1mA resolutions.  __ 

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

      <<<         >>> 


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

 


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



 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |   
Privacy Policy


Discovercircuits.com endeavors to credit original designers.   Please alert us by eMail so we can
delete links to material that have been copied without your permission
.   Thank you.


© Copyright of all original material on this website is the property
of David A. Johnson, P.E. (Dave Johnson & Associates ) unless otherwise noted.  

Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.
All material is provided "as is" without guarantees or warranty of any kind, either expressed or implied.