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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. :

UL Ground Resistance Tester -  UL requires that an electrical system using a metal chassis earth ground connection have a resistance of less than 0.1ohms.   This resistance must be tested with actual line current in excess or 10 amps.    The circuit shown uses a couple of LEDs to indicate. . . Circuit by Dave Johnson P.E.-April, 2001

Ultra Low Power Detects Clear Fluid -  Using an ultra low power technique, this circuit detects when a clear fluid is inside a piece of clear plastic tubing.  it can be used for fluid level control and monitoring . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Ultra Low Power Human Finger Detector -  The circuit below seems to work well and averages a current drain of only 10 microamps from a lithium cell.  it uses a single CA4013 dual D flip/flop.  One section is wired as a pulse generator.  it applies 10us 10ma pulses to a LED inside a slotted optical sensor at a rate of about 50Hz.  The phototransistor in the second half of the sensor detects the pulses and sends a pulse to the data input of the second flip/flop in the 4013 package.  if there is nothing between the LED and the phototransistor, the inverting output of the 4013 remains low.Circuit Solution by Dave Johnson P.E.-May, 2006

Under/Over Voltage Alarm on AC Line -  Power lines, which deviate much beyond normal voltages can damage expensive electronic equipment.  The circuit below sounds an alarm whenever the line voltage is higher or lower than normal.  I set the alarm limits at about +-15% from standard levels. . . Circuit by Dave Johnson P.E.-March, 2009

Unplugged Power Cord Alarm -  Many medical devices, such a portable X-ray and ultrasound equipment, carry their own batteries.  However, the frantic pace of some hospital emergency rooms might cause the device to be shoved off into a corner without being plugged back into an AC power source to recharge their batteries.  So, I designed this circuit to emit an audible alarm whenever the device’s power cord was unplugged from the wall for a period of time. . . Circuit by David Johnson P.E.-July, 2000

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:

U.S. Navy TV-3/U Tube Tester manual -  Vintage schematic__ 

UJT Test -  This testing procedure is for use with a digital multimeter in the OHM's test-range.  The UJT is a solid-state 3-terminal (TO-18 case) emiconductor.  UJT's are used in pulse/timing, oscillator, sensing, and thyristor triggering circuits.  The most common one being probably the 2N2646 from Motorola.   __ Designed by Tony van Roon  VA3AVR

UL Ground Resistance Tester -  UL requires that an electrical system using a metal chassis earth ground connection have a resistance of less than 0.1ohms.   This resistance must be tested with actual line current in excess or 10 amps.    The circuit shown uses a couple of LEDs to indicate. . . Circuit by Dave Johnson P.E.-April, 2001

Ultra High Sensitive Probe -  This circuit is so sensitive it will detect mains hum.  Simply move it across any wall and it will detect where the mains cable is located.  it has a gain of about 200 × 200 × 200 = 8, 000, 000 and will also detect __ Designed by Izhar Fareed

Ultra Low Power Detects Clear Fluid -  Using an ultra low power technique, this circuit detects when a clear fluid is inside a piece of clear plastic tubing.  it can be used for fluid level control and monitoring . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Ultra Low Power Human Finger Detector -  The circuit below seems to work well and averages a current drain of only 10 microamps from a lithium cell.  it uses a single CA4013 dual D flip/flop.  One section is wired as a pulse generator.  it applies 10us 10ma pulses to a LED inside a slotted optical sensor at a rate of about 50Hz.  The phototransistor in the second half of the sensor detects the pulses and sends a pulse to the data input of the second flip/flop in the 4013 package.  if there is nothing between the LED and the phototransistor, the inverting output of the 4013 remains low.Circuit Solution by Dave Johnson P.E.-May, 2006

Ultra Low Power LCD Indicator -  This circuit serves as an ultra-low power replacement for multiple LED on-off indicators.  it also has the advantage of being easy to read in full daylight.  With the parts shown, it is possible to display four bits of information.   __ Designed by G. Forrest Cook

UltraLow Power Standalone Motion Switch  -  Equipment Needed The following equipment is needed: , Bullet text, Getting Started Load the evaluation software by placing the CN0274 Evaluation Software CD into the PC.  Using My Computer, locate the drive that contains the evaluation software CD and open the Readme file.  Follow the instructions contained in the Readme file for installing and using the evaluation software.  CiRCUiT EVALUATiON AND TEST, Setup Connect the 120-pin connector on the CN0274 Evaluation Software to the connector on the EVAL-SDP-CS1Z__ Analog Devices from the Lab

Ultraprecise Current Sensing with LTC6102 -  Very low input offset allows using low value resistors while maintaining high measurement resolution.  Using low value also reduces power losses and temperature rise.  __ Linear Technology/Analog Devices App Note, Jul 2, 2012

Ultra-Simple Circuit Voltage Probe -  Detects 1.8 to 230 Volts DC or AC Minimum parts counting.  Circuit diagram: Parts: D1 5 or 3mm.  Red LED D2 5 or 3mm.  Green or Yellow LED LP1 220V 6W Filament Lamp Bulb P1 Red Probe P2 Black Probe Device purpose: This circuit is not a novelty, but it __ Designed by Flavio Dellepiane

Ultrasonic Distance Measurement with the MSP430 (PDF) -  This application report describes a distance-measuring system based on ultrasonic sound utilizing the MSP430F413 ultralow-power microcontroller.  The system transmits a burst of ultrasonic sound waves towards the subject and then receives the corresponding echo.  The MSP430 integrated analog comparator Comparator_A is used to detect the arrival of the echo to the system __ Designed by TI Application Report SLAA136A - October 2001

Ultrasonic Distance Measurer -  Linear measurement is a problem that a lot of applications in the industrial and consumer market segment have to contend with.  Ultrasonic technology is one of the solutions used by the industry.  However, an optimized balance between cost and features are a must for almost all target applications__ 

Ultrasonic distance meter using raspberry pi 2 -  Ultrasonic ranging module HC-SR4 provides 2cm to 4cm non-contact distance measurement range.  its accuracy can reach ±3mm__ Arnav Bansal

Ultrasonic Distant Obstacle Detector -  The first sensor a robot usually gets fitted with is an obstacle detector.  it may take three different forms, depending on the type of obstacle you want to detect and also — indeed, above all — on the distance at which you want detection to take place.  For close or very close obstacles, reflective iR__ 

Ultrasonic Proximity Detector -  We the humans can hear sound of up to 20kHz frequency only. This proximity detector works at a frequency of 40 kHz. it uses two specially made ultrasonic transducers: One transducer...__ Electronics Projects for You

Ultrasonic Proximity Detector 2 -  This ultrasonic proximity detector comprising independent, battery-powered transmitter and receiver sections makes use of a pair of matched ultrasonic piezoceramic transducers operating at around 40 kHz each.  This circuit can be...__ Electronics Projects for You

Ultrasonic Range Meter -  On these pages, I will introduce the Ultrasonic Range Meter with PIC 16F873.  As for the range meter which doesn't use PIC , refer to "Ultrasonic Range Meter".  I created the PCB pattern for this circuit using EAGLE CAD.  With this circuit, the following features of PIC 16F873 are used.   __ Designed by Seiichi Inoue

Ultrasonic Water Tank Level Gauge -  Do you have a tank to collect rainwater? Do you know how much water is in it? This ultrasonic tank level gauge fires an energy burst which bounces off the surface of the water ? and then a microcontroller calculates how far down the tank water level is.  Clever, eh! __ SiliconChip

Under/Over Voltage Alarm on AC Line -  Power lines, which deviate much beyond normal voltages can damage expensive electronic equipment.  The circuit below sounds an alarm whenever the line voltage is higher or lower than normal.  I set the alarm limits at about +-15% from standard levels. . . Circuit by Dave Johnson P.E.-March, 2009

Underground Locator Generator -  Schematic Only   for radiodetection® rd400 llts precision line trace unit (underground cable locator) (16f628)  __ Designed by Jon Fick

Understanding & selecting RMS voltmeters -  05/11/00  EDN Technical Article: Failing to verify ac-voltmeter accuracy before conducting rms-noise measurements may cause highly misleading results.   __ Circuit Design by Jim Williams and Todd Owen, Jim Williams, EDN's most revered contributor, passed away in June 2011 after a stroke.  He was 63.

Understanding Electricity-an analogy with water -  (good start for beginners)  __ Designed by Richard Torrens

Universal frequency counter & voltage meter -  For the purpose to be used with QRP transceivers I have developed some frequency counters with different types of displays (from simple 8 LED display to 2 x 8 character LCD) , but the f-counter described on this page I have found to be the most useful.  The requirements I wanted to fulfil with this design __ Designed by Aleksander Stare

Universal IR Remote Control Tester -  This tester consists of two integrated remote control receivers whose outputs drive an LED to indicate when a suitable infrared signal is received.  To cover all current infrared remote controls, one receiver (the TSOP1736) has maximum sensitivity to carriers at 36 kHz, the other (the TSOP1738) to carriers at 38 kHzmust register on this site __ Designed by Published in Elecktor July/Aug, 2010

Unplugged Power Cord Alarm -  Many medical devices, such a portable X-ray and ultrasound equipment, carry their own batteries.  However, the frantic pace of some hospital emergency rooms might cause the device to be shoved off into a corner without being plugged back into an AC power source to recharge their batteries.  So, I designed this circuit to emit an audible alarm whenever the device’s power cord was unplugged from the wall for a period of time. . . Circuit by David Johnson P.E.-July, 2000

Unusual clock with AT89C2051  -  interesting worked out example of clock with only 7 lad's   - published in magazine "Svijet elektronike" Nr.46 ( June / July 2004) Author: ivica Novakovic __ Designed by © Ivica Novakovic

USB 2.0 temperature sensor needs only a handful of parts -  05/24/07  EDN Design Ideas:  A USB-to-serial converter forms the heart of an accurate USB temperature sensor __ Circuit Design by Silvio Lauckner, Ismaning, Germany

USB Based Temperature Monitor using the ADuC7120 Precision Analog Microcontroller & an External Thermistor  -  Circuit linearization techniques can be accomplished in software; however, that will not be discussed here.  , Despite the powerful ARM7 core and high speed SAR ADCs, the ADuC7122 still provides a low power solution__ Analog Devices from the Lab

USB link neatly measures temperature -  26-Oct-00 EDN Design Ideas:  Figure 1 shows a convenient and neat way to measure temperature using the USB of a PC.  An ADM1023 IC senses the temperature, and an Anchor Chips EZ-USB.   PDF contains several circuits, scroll to find this one.    __ Circuit Design by Mary Burke, Analog Devices, Limerick, Ireland

USB-Based Thermocouple Temperature Measurement System using ARM7  -  in the source code, an ADC sampling rate of 4 Hz is chosen.  When the ADC input PGA is configured for a gain of 32, the noise free code resolution of the ADuC7060/ADuC7061 is greater than 18 bits.  , Circuit Function and Benefits, The following features of the ADuC7060/ADuC7061 are used in this application:, Primary 24-bit Σ-Δ ADC with programmable gain amplifier (PGA) : The PGA is set for a gain of 32 in the software for this application.  ARM7TDMi® core: The powerful 16-/32-bit ARM7 core with integrated 32 kB flash and SRAM memory runs the user code that configures and controls the ADC, processes the ADC conversions from the RTD, and controls the communications over the UART/USB interface__ Analog Devices from the Lab

USB-Based, Thermocouple Temperature Measurement System using ARM Cortex-M3  -  in the source code, an ADC sampling rate of 4 Hz is chosen.  When the ADC input programmable gain amplifier (PGA) is configured for a gain of 32, the noise-free code resolution of the ADuCM360/ ADuCM361 is greater than 18 bits.  , Circuit Function and Benefits, The following features of the ADuCM360/ADuCM361 are used in this application: , A 24-bit Σ-Δ ADC with a PGA set for a gain of 32 in the software for the thermocouple and RTD__ Analog Devices from the Lab

Use a heated diode as a Flow sensor -  12/23/13  EDN Design Ideas:  A hot diode senses air or fluid flow __ Circuit Design by Raju Baddi

Use a PC's parallel port to program a clock source -  12/07/04  EDN Design Ideas:  This Design idea shows how you can use Linear Technology's LTC6903 programmable oscillator as a clock source for direct-digital synthesis, data conversion, switched-capacitor filtering, clock, and voltage-controlled oscillator circui __ Circuit Design by William Grill, Honeywell BRGA, Lenexa, KS

Use a Photoelectric-FET Optocoupler as a Linear Voltage-Controlled Potentiometer -  01/19/12 EDN Design Ideas:  The circuit takes advantage of an identical photo-FET as a feedback element.  You can use a photoelectric FET as a variable resistor or a potentiometer in combination with a fixed resistor.  The H11F3M photoelectric FET has an isolation voltage of 7.5 kV, enabling you to safely control highvoltage circuit parameters.  The nonlinear-transfer characteristics of these devices are problematic, however (Figure 1).  To correct the nonlinearity, using a simple feedback mechanism as a potentiometer yields a linear response (Figure 2).  This circuit uses two photoelectric FETs—one for feedback and the other for applications requiring an isolated potentiometer.  You connect the inputs of the two photoelectric FETs in series to ensure the same amount of current for the input LEDs.   __ Circuit Design by Sajjad Haidar, University of British Columbia, Vancouver, BC, Canada

Use a PWM fan controller in an EMI-susceptible -  02/16/06  EDN Design Ideas:  Control it with either an external negative-temperature-coefficient thermistor or a PIC  microcontroller and its SMBus serial-data bus __ Circuit Design by Dimitri Danyuk, Niles Audio Corp

Use a switching-regulator controller to generate 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

Use a Transistor & an AM meter to Measure Inductance -  04/05/12  EDN Design Ideas:  Bipolar junction transistors transfer a current from a lower-resistance emitter to a higher-resistance collector.  You can use this property to measure inductance.   __ Circuit Design by Raju Baddi, Tata Institute of Fundamental Research, Pune, India

Use AIR-Core-Coil Resistance to Estimate Inductance -  EDN-Design ideas -- 01/05/12    if the coil is tightly wound you do not need the number of turns to calculate inductance. __ Circuit Design by Peter Demchenko, Vilnius, Lithuania

Use op-amp injection for Bode analysis -  16-Sep-04 EDN Design Ideas:  Bode analysis is an excellent way to measure small-signal stability and loop response in power-supply designs.  Bode analysis monitors gain and phase of a control loop.  it performs this monitoring by breaking the feedback loop and injecting a signal into the feedback node and then comparing the injected signal with the output signal of the control loop __ Circuit Design by Martin Galinski, Micrel Semiconductor, San Jose, CA

Use RS-232C port to measure pressure -  08/01/97 EDN Design Ideas:  A simple circuit and accompanying software turn a pressure sensor into an accurate and cheap pressure digitizer that works with any PC's RS-232C COM port.  Many manufacturers make micromachined silicon piezoresistive pressure sensors __ Circuit Design by W Stephen Woodward, University of North Carolina--Chapel Hill

Use Thermoelectric Coolers with Real-World Heat Sinks -  04/17/08  EDN Design Ideas:  When using a Peltier thermoelectric cooler with a less-than-perfect heat sink, you must derate the maximum voltage and current applied to the cooler __ Circuit Design by W Stephen Woodward, Chapel Hill, NC

Use Thermostat as 12 Volt Timer -  Find out how an old battery powered thermostat can be used as a low voltage automatic timer.   __ Designed by REUK-Renewable Energy UK website

Use your printer port as a high-current AM meter -  07/06/00 EDN Design Ideas:  With a few inexpensive components and iNT1Ch, you can turn the printer port of your PC into a high-current ammeter.    __ Circuit Design by K Suresh, Indira Gandhi Centre for Atomic Research, Kalpakkam, India

Using the LTC1325 Battery Management Ic -  AN64 App Note 64 details characteristics of various battery types and appropriate charging management schemes.  The LTC1325 battery management IC is highlighted along with information for applying it to any type battery.  Techniques and circuitry for conditioning, charging and monitoring NIC d, NiMH
, Li-ion and Lead-Acid batteries are presented.  __ Linear Technology/Analog Devices

Using Vector Modulation Analysis in the Integration, troubleshooting & Design of Digital RF Communications Systems -  Application Note__ Aligent

UTP Cable Tester -  Warning!  This design is some 16 years old by now.  Although it will still work, I recommend you to buy a ready made cable tester, unless you enjoy building one your self, even if it'll cost you much more than one you can buy ready made.  __ 

UVP protects rechargeable batteries -  EDN Design Ideas:  04/11/2016    Protect rechargeable batteries from deep discharge with this UVP & load switch. __ Circuit Design by Peter Demchenko

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

 


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