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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. :
Switch activated by Piezo Vibration -  An inexpensive piezo wafer is used to detect vibration and when the vibration is sufficient a switch is activated . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

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:

Star Delta Wiring Calculator -  An online calculator to work out the output voltage and current for an alternator wired in star or delta configuration.   __ Designed by REUK-Renewable Energy UK website

Static Charge Monitor -  Yes, you read correctly, it's a ghost detector, assuming ghosts exist and, for some reason, have electric charge.  Ok, this is a changing charge detector.  if a ghost disturbs the electric field in the vicinity of this gadget you will see the results on the LEDs.  Don't hold your breath, unless you wish to become a ghost yourself.  There's a pair 'a normal LEDs that display whether the charge at the antenna is changing in a positive or negative direction (green vs red).   __ Designed by Lennie Zink

Status Indicator Flags Five Discharge States -  01/20/94 EDN Design Ideas:  The circuit actually indicates five conditions of the battery.  A steady glow assures the user that the battery is strong and healthy.  A2-Hz brief flicker off indicates that the battery is starting to show age.  A more insistent, 50%, 5-Hz flashing is a warning to have a spare battery on hand.  A brief flicker __ Circuit Design by Glen Chenier, Fitel Photomatrix, Nepean, ON, Canada

Step Km Counter Max -  Pedometer has a range of 9.950 meters with2-digits.  Slip it in pants pocket for walking and jogging __ Contact Flavio Dellepiane, fladello @ tin.it

Step-Km Counter -  Pedometer has a range of 9.950 meters with2-digits.  Slip it in pants pocket for walking and jogging __ Designed by RED Free Circuit Designs

Stereo Potentiometer -  in PDF format, text in Finnish__ 

Stereo Test Tone Generator -  This circuit produces two audio frequency sine waves with different frequencies but equal amplitudes.  it can be used for testing a variety of stereo audio equipment.  The circuit was originally developed the purpose of aligning an FM Stereo Modulator, like the type used in low power FM stereo transmitters.  Two tone outputs are available, the low tone has a secondary output that is 180 degrees out of phase with the primary output.  The circuit is also handy for testing computer sound card inputs.  A variety of waveform configurations can be produced by plugging a stereo audio patch cord into the four output jacks. __ Designed by G. Forrest Cook

Stereo-VU-Meter -  Dieses Stereo-VU-Meter ist sehr simpel aufgebaut und lässt sich einfach an ein Line Audio-Signal hängen.  Dann zeigt es den Signalpegel mit 10 Leuchtdioden pro Kanal an.  Diese Schaltung hat keinen Verstärker vorgeschaltet, weshalb der __ Designed by Text in German

Strain Meter -  This strain meter shows whether the strain is compressive (reducing the length) or tensile (increasing the length) when an object such as a strut on a crane changes its shape.__ Electronics Projects for You

Strain sensing using optical phase interrogation technique with polymer optical fiber -  EDN Design Ideas:  07/16/2015   Optical phase interrogation with polymer fiber offers an easy to handle and integrate strain sensing solution __ Circuit Design by Avago Tech Note

Stress Meter -  This project comes with all parts, PC board and a pre-programmed chip for STRESS METER.  But you are encouraged to add more sub-routines to the program and learn to program the chip yourself.  You will need the "Chip Programmer Model F" and the software provided below
 __ Contact Collin Mitchell

Stress Meter Circuit Diagram with Full Explanation -  ContentsWhat is a Stress Meter? Stress Meter: Circuit Explanation Assembly and usageStress meter lets us access our emotional pain in an electronic format.  With the help of this device one...__ Electronics Projects for You

Sub-picofarad measurement with CMOS inverters -  EDN Design Ideas:  10/06/2014     Measure capacitance down to 2.5pF full-scale using this hex inverter-based design __ Circuit Design by Raju Baddi

Sudden ionospheric disturbance (SID) receiver -  The AAVSO SiD Program consists of solar observers who monitor very low frequency (VLF) radio stations for sudden enhancements of their signals.  Earth's ionosphere reacts to the intense X-ray and ultraviolet radiation released during a solar flare.  The ionospheric disturbance enhances VLF radio propagation.  By monitoring the signal strength of a distant VLF transmitter, sudden ionospheric disturbances (SiDs) are recorded and indicate a recent solar flare event. __ Contact AAVSO SID Program

Sump Pump Controller -  Every sump pump controller that I have seen on the web uses DC to sense the water.  This approach is simple, but eventually causes corrosion of he sensor probes due to the electrolysis.  The probes than have to be periodically cleaned or replaced.  This c __ Designed by Andrew R. Morris

Sun tanning timer -  This timer was designed for people wanting to get tanned but at the same time wishing to avoid an excessive exposure to sunlight.  A Rotary Switch sets the timer according to six classified Photo-types (see table).  A Photo resistor extends the preset time value according to sunlight brightness (see table). __ Contact Flavio Dellepiane, fladello @ tin.it

Super Probe, 16 functions with very few parts -  The Superprobe project was designed to see how much could be done with a PIC  chip and just a few parts.  The image at the right shows the capacitance measuring mode.  This device is designed around a PIC 16F870, a 4 digit LED display module and very little else.  [img:eb8cceb438]http://www.  circuitdb.  com/download.  php?fileiD=135[/img:eb8cceb438] [i:eb8cceb438]Note: I have recieved a lot of inquiries on this project.  To date, several have been duplicated world-wide.  Many have been constructed in other types of cases.  As long as the circuit is wired as shown, and the object code (below) is__ 

Super Simple Circuit SONAR -  Thomas Scarborough's electronics design have been popular.  Here, therefore, is a super simple SONAR (designed by him).  SONAR stands for SOund NAvigation Ranging.  it is a technique which is used to determine the distance and direction of objects by acoustic means -- usually in water, but also in air.  The SONAR described here has the most basic functionality -- it simply reports the existence of an object up to a few metres’/yards’ distance.  it would, for example, shriek when a reversing vehicle approached a wall (X1 and X2 would be mounted just far enough apart NOT to shriek until the__ 

Superprobe -  The Superprobe project was designed to see how much could be done with a PIC  chip and just a few parts.  The image at the right shows the capacitance measuring mode.   __ Designed by Luhan Monat - Mesa Arizona

Super-Sensitive 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.

Supervisory IC makes Simple Circuit line Monitor -  03/01/96 EDN Design Ideas:  You can use the MC34161P universal voltage monitor to build a simple ac power-line monitor (a voltage-sensing relay).  in this application (Figure 1) , the mode select pin (pin 7) connects to the internal 2.55V reference (pin 1) , and the IC functions as a positive-voltage window detector.  A small signal transformer provide as total isolation from the power lines and performs a unique role in the circuit.  During the positive half cycles of the line voltage, the transformer functions as a conventional power transformer feeding a 15V power supply through a half-wave rectifier.   __ Circuit Design by Henno Normet, Tavares, FL

Supervisory Monitors-modem connection -  04/09/98 EDN Design Ideas:  (Scroll to find this circuit) in telemetry or security applications in which a modem connection automatically establishes itself between two systems, a failure in one of the systems can interrupt the data exchange while the connection remains established until someone physically breaks the line or restarts the failed system.  This situation __ Circuit Design by J Basilio Simies and Jorge Landeck, Instrumentation Center of the University of Coimbra, Coimbra, Portugal

Supply Voltage Monitor -  A circuit for monitoring supply voltages of ±5 V and ±12 V is readily constructed as shown in the diagram.  it is appreciably simpler than the usual monitors that use comparators, and gates.  The circuit is not intended to indicate the level of the inputs.  in normal operation, transistors T1 and T3 must be__ 

Switch activated by Piezo Vibration -  An inexpensive piezo wafer is used to detect vibration and when the vibration is sufficient a switch is activated . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

Switch controls digital potentiometer -  02/27/02  EDN Design Ideas:  The control of electronic potentiometers in most today's applications comes from controller-generated signals.  However, a significant number of applications exist that require adjustments using manual, front-panel controls.  The circuit in Figure 1 uses one IC , one switch, and 10 discrete components __ Circuit Design by Chuck Wojslaw and Gary M Craig, Catalyst Semiconductor, Sunnyvale, CA

Switchable RF Probe/Watt Meter for the FM Transmitters -  This unique project is one of the most trusted homemade test instruments to have, once you get your FM transmitter up and running !  !  ! This simple little device is capable of finding your FM transmitters' __ Designed by braincambre500 @ yahoo.com

Switching-regulator generates fast pulses -  04/13/06  EDN Design Ideas:  Switching-regulator-controller ICs  can deliver gate-drive pulses with rise and fall times of less than 2 nsec, making them ideal candidates for laboratory pulse-generators __ Circuit Design by Mitchell Lee, Linear Technology Corp

SWR Bridge 1 to 1000 Mhz (1GHz) -  This SWR bridge is not my own invention, OZ3SW and OZ9MO has improved the design after DJ7VY construction in ukw-berichte 1/83.   This is a construction set made for the members of Frederikssunds EDR Club, all I did was a bit of gluing and soldering.  Thanks for all the hardware help, parts help, calibrating and measuring !  you know who I mean ! !  __ Designed by Thomas Scherrer OZ2CPU

SWR/Pwr meter -  The figure gives the circuit diagram of an SWR/POWER meter that can be built using an existing SWR/"POWER" meter.  These instruments have two meters, one for relative power and the other for SWR indications.  The problem with these meters is that the readings are very frequency conscious and there exists no point of calibration to set the in-built potentiometer.  All this can be overcome.   __ Designed by Harry Lythall-SM0VPO

Sylvania 145 Audio Oscillator schematic -  Circuit Only __ Designed by Sylvania

Synthetic Isolators -  Test Equipment-great for checking the SWR of antennas, Amplifiers, mixers, etc.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

System Cabling Errors & DC Voltage Measurement Errors in Digital Multimeters 5988-5511EN -  Application Note__ Aligent

System Monitor with Instrumentation-Grade Accuracy Used to Measure Relative Humidity -  A psychrometer is a type of hygrometer, a device that measures relative humidity.  it uses two thermometers, one dry (dry bulb) and one covered in a fabric saturated with distilled water (wet bulb).  Air is passed over both thermometers, either by a fan or by swinging the instrument, as in a sling psychrometer.  A psychrometric __ Linear Technology/Analog Devices App Note, Jan 30th 2012

System Monitors multiple temperatures, controls fan speed -  10/12/00 EDN Design Ideas:  The block diagram in Figure 1 represents a complete remote-temperature-sensing and fan-control system.  The system uses an Analog Devices temperature-monitor and fan-control ASIC  and a PIC 16C84 µC from Microchip Technology.  The ADM1022 allows you to measure the local temperature and two remote temperatures within a system.  An on-chip, 8-bit DAC controls the speed of a cooling fan in response to the measured temperature.    __ Circuit Design by David Hanrahan, Analog Devices Inc, Limerick, Ireland

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