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Tester or Measurement (Instrument) Circuits

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

Pulsed LED Test Circuit -  This circuit is designed to test visible and infrared LEDs in pulsed mode operations.  it can drive the LED with peak currents in excess of 10 amps.  A light detector nearby can monitor the response time and intensity of the LED under test. . . Circuit by Dave Johnson P.E.-June, 2000

Pushbutton Oneshot & Latch -  This circuit uses a single IC to convert a noisy pushbutton switch signal into a clean pulse or a sustained push on-push off signal.  it can operate from 3v to 18v. . . Circuit by David A. Johnson P.E.-March, 2002

PV Solar Cell Test Fixture -  This is an illustration of a test fixture, which can be used to test individual solar cells for short circuit current.  Using a PIN photo diode and a control circuit, the solar cells can be tested under constant light level conditions . . . Hobby Circuit designed by David A. Johnson P.E.-October, 2006

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

Provide High-Side Current-Sensing for White-LED Drivers -  02/19/04  EDN Design Ideas:  White LEDs find wide use in backlighting color-LCD screens in most portable devices, such as cellular phones, PDAs, and MP3 players.  Multiple LEDs often connect in series to ensure that the same current flows through every LED.  To  __ Circuit Design by Dimitry Goder, Sipex Corp, San Jose, CA

Provide ISFET-sensor bias -  10-Jun-04 EDN Design Ideas:  iSFETs (ion-sensitive field-effect transistors] are useful for measuring the acidity of fluids.  Accurate measurements require that the iSFET's bias conditions (iD and VDS] be held constant while the gate is exposed to the fluid under __ Circuit Design by Brian Harrington, Analog Devices, Wilmington, MA

Provide Simpler Power-Supply-Sequence Testing -  3-Dec-09 EDN Design Ideas:  New circuit improves on an earlier power-sequence-testing idea __ Circuit Design by Dan Karmann, DLK Engineering, Thornton, CO

Provides 1.5v, 7a Bus Termination -  09/14/95  EDN Design Ideas:  Some of the newest high-performance processors require a 1.5V bus terminator that can source currents as high as 7A.  This terminator requires a very fast transient response, because the device must react to high peak-current changes that have extremely fa __ Circuit Design by Chester Simpson and Mineo Yamatake, National Semiconductor, Santa Clara, CA

Provides Visual Verification of IR Pulses -  09/08/11  EDN Design Ideas:  Use a transimpedance amplifier to drive an LED.  You can test an IR (infrared) link with a circuit that converts an iR-generated photocurrent to an amplified current that drives a standard LED (Figure 1).  This approach provide as a visual feedback to indicate that the transmitter is working.  The circuit can be enclosed in a small plastic or metal box and requires just a 9V transistor battery for operation.  Diode D1 is a basic Everlight PD333-3C/H0/L2 or equivalent IR photodiode in a T1ľ package.   __ Circuit Design by Michael J Gambuzza, General Electric Measurement and Control Solutions, Billerica, MA

Providing Fixed Power Gain at the Output of an IQ Modulator  -  The adjacent channel power ratio (ACPR) of a single carrier, wideband code division multiple access (WCDMA) signal has become a popular metric for assessing the system level distortion of a circuit (that is, as opposed to an assessment that is solely based on iP3 and iMD levels) __ Analog Devices from the Lab

Proximity Alarm -  This simple circuit is sure to have the police beating a path to your door, however, it has the added advantage of alerting you to their presence even before their footsteps fall on the doormat.  The circuit transmits on Medium Wave (this is the small problem with the police).  IC 1a, together with a sensor (try a 20cm x 20cm sheet of tin foil) oscillates __ Designed by Rev. Thomas Scarborough

Proximity Detector -  Here is a Simple but Very Effective One __ Designed by G.L. Chemelec

Pseudodifferential Multichannel Bridge Digitizer & Digital Cold Junction Compensation -  This circuit enables pseudodifferential measurements of several bridge transducers and absolute temperature measurement.  Consecutive readings are performed on each side of the bridge by selecting the appropriate channel on the LTC2428.  Each output is digitized and the results digitally subtracted to obtain the pseudodifferential __ Linear Technology/Analog Devices App Note, Apr 29th 2010

Pseudologarithmic thermistor signal conditioning spans wide temperature range -  6-Jan-05 EDN Design Ideas:  Given its low cost, small size, robust construction, accuracy, versatility and sensitivity, it's no wonder that the thermistor rates as one of the most popular temperature sensors available.  However, in some applications, a thermistor can exhibit too much sensitivity for wide-range temperature measurements __ Circuit Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC

Pulse Generator & Signal Tracer -  This simple circuit generates narrow pulses at about 700-800Hz frequency.  The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes.  A high-pitched tone can be heard from the speaker of the device under test when all is working properly.__ Learning Electronics

Pulse generator aids IC testing -  09/01/09 Test & Measurement World:As ICs  increase in complexity and decrease in size, their pin counts drop or, at best, remain constant.  The result: a need for pin-saving measures like serial programming.  in the past, multiple pins might have been available for programming an IC ’s current or voltage limit, but today’s ICs  often encode that limit as a set number of pulses on a serial line.  -- [Kevin Frick, integrated Products, Sunnyvale, CA]__ 

Pulse Generator Verifies Test Setups -  05/26/94 EDN Design Ideas:  Verifying the rise-time limit of wideband test-equipment setups is a difficult task.  in particular, you must often know the "end-to-end" rise time of an oscilloscope/probe combination to ensure measurement integrity.  Fig1s circuit provide as an 800-psec pulse having rise __ Circuit Design by Jim Williams, EDN's most revered contributor, passed away in June 2011 after a stroke.  He was 63.

Pulse Induction Metal Detector part 1 -  Experimental system for overcoming magnetic viscosity effects. __ Designed by JA Corbyn

Pulse Induction Metal Detector part 2 -  The bandpass amplifier in Fig.11 extracts possible signals for the background noise caused mainly by transients in the circuits. __ Designed by JA Corbyn

Pulse Oximeter via Finger Clip Reference Design with BLE Connectivity -  This reference design is for a complete SPO2 Pulse Oximeter finger clip end equipment featuring TI signal chain, power, and connectivity components. With Ti’s AFE4490 Pulse Ox AFE, you can accelerate and simplify your pulse ox design while still ensuring the highest of quality clinical measurements. This reference design also includes a full BLE connectivity design for easy interface to BLE enabled smartphones, tablets, etc.__ Texas Instruments

Pulse Rate Meter -  Here is a meter to measure the human heart rate.  The pulses are picked up around the wrist (just as it is examined by the doctor) using a condenser microphone fastened...__ Electronics Projects for You

Pulse Rate Monitor -  This simple circuit enables you to listen to your heartbeat, for instance, while you are exercising.  The transducer used for detecting the pulse is an electret microphone, X1 in the diagram.  The model used has two (polarized) terminals.  As usual with this type of microphone, it functions via a series resistor, R1.  The potential drop__ 

Pulse rate Monitor using TLC274 opamp -  This simple circuit enables you to listen to your heartbeat, for instance, while you are exercising.  The transducer used for detecting the pulse is an electret microphone, X1 in the diagram.  The model used has two (polarized) terminals.  As usual with this type of microphone, it functions via a series resistor, R1.  The potential drop across this resistor__ Learning Electronics

Pulse Reading Logic Probe -  This circuit uses LEDs to display logic states for high, low, rising pulse, and falling pulse, it is generally useful for debugging logic circuitry. __ Designed by G. Forrest Cook

Pulsed LED Test Circuit -  This circuit is designed to test visible and infrared LEDs in pulsed mode operations.  it can drive the LED with peak currents in excess of 10 amps.  A light detector nearby can monitor the response time and intensity of the LED under test. . . Circuit by Dave Johnson P.E.-June, 2000

Pulse-Generator & Signal-Tracer -  Dual-purpose test-instrument; Very simple circuitry, 1.5V Battery-operated __ Contact Flavio Dellepiane, fladello @ tin.it

Pushbutton on/off control for battery-powered Device, with automatic turn-on when the Device is plugged in -  This circuit shows a typical LTC2955-1 application for a handheld device.  The 3.6V supply is produced directly from the handheld’s battery; the 12V secondary supply comes from a wall adapter.  Both the 3.6V and 12V inputs are connected to the LT3060 regulator input via diode-OR so that either supply can power the system.  The __ Linear Technology/Analog Devices App Note, Jun 29th 2012

Pushbutton Oneshot & Latch -  This circuit uses a single IC to convert a noisy pushbutton switch signal into a clean pulse or a sustained push on-push off signal.  it can operate from 3v to 18v. . . Circuit by David A. Johnson P.E.-March, 2002

Pushbutton replaces rotary switch -  26-Oct-00 EDN Design Ideas:  The problem of setting any one of four modes of aµC-operated process has a straightforward solution  Have the µC check the states of some 4 bits of aµC.    __ Circuit Design by Abel Raynus, Armatron International Inc, Melrose, MA

Pushbutton switch controls power supply & µC -  09/25/97 EDN Design Ideas:   Switching handheld units on and off with a pushbutton switch is a desirable feature.  Thus, switching-regulator/ controller ICs  for battery-powered applications provide a logic input to switch the device to a shutdown mode.  This type of shutdown pin can require additional components __ Circuit Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC

Pushbuttons & digital potentiometer control boost converter -  02/17/05 EDN Design Ideas:  Digitally controlled potentiometers are useful for generating analog control voltages under the control of a microcontroller.  in some applications, manual pushbutton switches could replace a microcontroller and simplify product design.  Mechanical switches exhibit contact bounce, and, when a user actuates them, they may open and close many times before reaching a stable state __ Circuit Design by Simon Bramble, Maxim Integrated Products Inc, Wokingham, UK

PV Solar Cell Test Fixture -  This is an illustration of a test fixture, which can be used to test individual solar cells for short circuit current.  Using a PIN photo diode and a control circuit, the solar cells can be tested under constant light level conditions . . . Hobby Circuit designed by David A. Johnson P.E.-October, 2006

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

Pyroelectric Fire Alarm -  Here is an ultra-sensitive fire sensor that exploits the direct piezoelectric property of an ordinary piezo element to detect fire.  The lead zirconate titanate crystals in the piezo element have the...__ Electronics Projects for You

Quad, 24 to 1, DC to 110 MHz Biomedical instrument switch matrix (Reed Relay) -  This Quad, 24:1 RF switch matrix was built for a multI channel biological specimen impedance meter.  The eight layer PCB was designed with Coplanar waveguide over groundplane and Stripline techniques for very low crosstalk and low loss performance.  One of the key tasks of this design was to minimize the path loss as test signals would be "bounced" off the biological specimen __ Designed by Steve Hageman

Quadrature Detection -  08/17/12  EDN Design Ideas:  (Originally published in the August 22, 1985, EDN-Design ideas) A circuit generates an output voltage that you can measure to determine whether two sine waves have a quadrature relationship.  The circuit in Figure 1 generates an output voltage that you can measure to determine whether two sine waves have a quadrature relationship.  if the output voltage is 0V, the inputs (ϕ1 and ϕ2) are exactly in quadrature.  if the inputs are other than 90° out of phase, a dc voltage appears at the circuit’s output.   __ Circuit Design by SL Black and HL Maddox, AT&T Technologies, Columbus, OH

Quartz Crystal Tests -  Two simple test circuits to check operation of quartz crystals __ Designed by Andy Collison

Quartz crystal-based remote thermometer features direct Celsius readout -  03/17/05 EDN Design Ideas:  Although quartz crystals have served as temperature sensors, designers haven't taken advantage of the technology because few manufacturers offer the sensors as standard products (references 1 and 2].  in contrast to conventional resistance- or semiconductor-based sensors, a quartz-based sensor provide as inherently digital-signal conditioning, good stability, and a direct digital ou __ Circuit Design by Jim Williams and Mark Thoren, Linear Technology Corp

Quick on-board Junction Tester -  Acoustic check of transistor and diode junctions; Also suitable as continuity tester __ Contact Flavio Dellepiane, fladello @ tin.it

Quickly estimate an electronic system's cooling requirements -  05/12/05 EDN Design Ideas:  Evaluate fan capacity versus thermal load __ Circuit Design by James Gabel, Thermo Electron Corp, San Jose, CA

Quickly find PC-Board shorts with low-cost tracer technique -  25-Nov-04 EDN Design Ideas:  A predominant failure mechanism for production pc boards is shorted traces.  Finding hidden shorts is often time-consuming and frustrating.  Typical techniques of cutting traces, lifting pads, and "blowing" shorts are, at best, questionable because they may affect the reliability of the circuit, and the ever-decreasing geometries and lower voltage ICs  make these practices tricky and risky __ Circuit Design by Teno P Cipri, Engineering Expressions Consulting

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

 


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