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Tester or Measurement (Instrument) Circuits

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Last Updated: November 30, 2017 02:27 PM
Circuits Designed by Dave Johnson, P.E. :
6v NMH/NiCd Battery Tester -  I designed this circuit to test rechargeable six volt battery packs under constant current conditions.  As designed, the circuit applies a 10 amp load to the battery pack.  A heat sink must be used on the main power transistor. . . Circuit by David Johnson P.E.-December, 2004

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:

48V Low Side Precision Current Sense -  This amplifier configuration is essentially the complementary implementation to the classic high-side configuration.  The op amp used must support common-mode operation at its lower rail.  A floating shunt-regulated local supply is provided by the Zener diode, and the transistor provides metered current to an output load __ Linear Technology/Analog Devices App Note, Mar 31, 2010

48V Power Monitor with Opto-Isolated Serial Interface -  The LTC4151 is a high side power monitor that operates over a wide voltage range of 7V to 80V.  in default operation mode, the onboard 12-bit ADC continuously measures high side current, input voltage and an external voltage.  Data is reported through the i2C interface when polled by a host.  The LTC4151 can also perform on-demand__ Linear Technology/Analog Devices App Note, Apr 26th 2010

48V Supply Current Monitor with Isolated Output & 105V Survivability -  The HV version of the LTC6101 can operate with a total supply voltage of 105V.  Current flow in high supply voltage rails can be monitored directly or in an isolated fashion as shown in this circuit.  The gain of the circuit and the level of output current from the LTC6101 depends on the particular opto-isolator used.  __ Linear Technology/Analog Devices App Note, Mar 30th 2010

4-Channel Digital Logic Analyzer & 5 Channel Digital Oscilloscope by using PC Parallel Port -  This is one of the simplest circuit for a PC parallel port based DLA.  The Circuit is mainly used to protect the port which is fabricated on the motherboard itself.   __ Designed by Huzaifa S. Sidhpurwala, India

5 Watt 80 Meter QRP CW Transceiver -  A great deal of interest has been generated by my previous design articles, so I decided to go to work on a full blown transceiver design.  After several months of work, the ROSE-80 transceiver was born.  This transceiver is similar to other designs but contains some unique differences.  This design boasts the following features__ 

50 kHz to 70 MHz Spectrum Analyzer-K7TAU -  Schematic only __ Designed by va3iul

50 MHz Frequency Counter -  This project is nice and small frequency counter that reads frequency from 1 Hz to 50 MHz that I have modified from original designed by Weeder Technologies.  I have designed new PCB to fit with 16X1 LCD and change source code for compatible with new small PCB Specifications, Auto-ranging with floating decimal point.  , Up to 7 digits displayed on 1X16 LCD.  , Auto-adjusting gate speed (0.1sec to 1 sec).  , Microcontroller-based circuitry provides for simplicity, ease of assembly, and highly stable readout.  , Sensitivity approximately 100 mV RMS (100 Hz to 2 MHz) , 800 mV RMSAT50 MHz.  , input overload protected.  __ 

50 MHz Frequency Counter Voltage Meter & SWR/PWR Indicator -  This is a successor of the PIC 16C71 4-digit LED f-counter & V-meter.  Some hard to find parts used in the previous version, which are out of production for some time, has been omitted.  A rather early PIC 16C71 has also been replaced by 28-pin device PIC 16F876 __ Designed by Aleksander Stare

500 Load & Power Meter -  A 50Ω dummy load is a simple but crucial piece of test equipment.  Not to perform tests on its own, but to provide a good testing environment.  A common test is output power of a transmitter, or a stage within a transmitter.  At QRP power levels of 5 watts or less, it becomes very practical to combine a dummy load and power meter into a terminating power meter __ Designed by Bobromwell

500 V Common-Mode Voltage Current Monitor  -  The input voltage to the AD7171 ADC is converted into an offset binary code at the output of the ADC.  The code is processed in the PC by using the SDP hardware board and LabViEW Evaluation software in Figure 3.  __ Analog Devices from the Lab

500W Low cost 12V to 220V inverter -  Using this circuit you can convert the 12V dc in to the 220V Ac.  in this circuit 4047 is use to generate the square wave of 50hz and amplify the current and then amplify the voltage by using the step transformer.   __ Designed by Ashad Mustufa

50-Watt DC Electronic Load -  Easy-To-Build circuit is ideal for testing DC power supplies, shunt regulators and constant current sources.__ SiliconChip

555 Based IR Proximity Detector -  Scroll down for this project.     Sometimes you want a simple solution to a problem and you don't mind if your main controller has to do the work.  This iRPD requires the main robot processor to choose which side to look at, and requires it to "debounce" the results for reliably operation.  But, it still works really well without any complex program code. __ Designed by Dennis Clark

555 Based IR Proximity Detector -  Sometimes you want a simple solution to a problem and you don't mind if your main controller has to do the work.  This iRPD requires the main robot processor to choose which side to look at, and__ 

555 Go No/Go Tester -  This is a more advanced unit with a precise timed testing procedure.  R1 (2M2) is same as 2.2 MegOhm.  The two timers determine the allowable accuracy for the timer IC under test.  Potentiometers P1 and P2 permit ready adjustment for the desired range.   __ Designed by Tony van Roon  VA3AVR

555 Timer IC Tester -  The 555-tester above is basically a LED flasher circuit but with the 555 removed.  imagen the output being a square-wave pulse with a high and low pulse, and is so indicated by the two leds, one 'Hi' and the other one 'Lo'.  When you have a good 555 under test.   __ Designed by Tony van Roon  VA3AVR

555 Timer Tester -  Test 555 timers quickly with this simple circuit.__ 

5V From Portable Wind Turbine -  This project deals with the design and development of a portable wind turbine unit, capable of generating electricity from the kinetic energy in the wind.  The circuit requires a DC motor, ...__ Electronics Projects for You

5V System Protected from 24V Power Supplies & Overcurrent -  The LTC4362 monolithic overvoltage/overcurrent protector safeguards 2.5V to 5.5V systems from power supply overvoltage.  it is designed for portable devices with multiple power supply options including wall adaptors, car battery adaptors and USB ports.  The LTC4362 features a soft-shutdown controlled by the ON pin and drives__ Linear Technology/Analog Devices App Note, Jul 8th 2011

5V/1A Power Supply -  Tendency of entry: 220V AC; Tendency of expense: 5V DC; Current of expense: 1A __ Designed by Kyriakos Kontakos

6 Digit 40MHz Frequency Counter Module -  Here is a design for a very low cost 6-digit frequency counter module using offshelf components (and not that expensive 74C926!).  The standard circuit will display directly in Hz (1MHz max) , and re is a separate on board divider that will allow you to display directly in KHz (approx 40MHz max).  Becausedisplay reads directly in Hz or KHz re is no __ Designed by David L. Jones

6-Decade Capacitance Substitution Box -  When breadboarding or prototyping, sometimes you need to experiment with a capacitor value.  Substituting a range of different capacitors can be a bit tedious.  What you need is a capacitance decade box, which makes it easy to find the right value for your circuit.__ SiliconChip

6v NMH/NiCd Battery Tester -  I designed this circuit to test rechargeable six volt battery packs under constant current conditions.  As designed, the circuit applies a 10 amp load to the battery pack.  A heat sink must be used on the main power transistor. . . Circuit by David Johnson P.E.-December, 2004

7.4mA DC Supply from 4mA to 20mA Current Loop -  The LTC3255 is a switched-capacitor step-down DC/DC converter that produces a regulated output (2.4V to 12.5V adjustable) from a 4V to 48V input.  in applications where the input voltage exceeds twice the output voltage, 2:1 capacitive charge pumping extends output current capability beyond input supply current limits.  At no __ Linear Technology/Analog Devices App Note, Sep 19th 2013

741 Based Light Sensor -  The circuit as shown act as a light sensor.  Under normal conditions the resistance of the LDR is high, keeping pin 2 low.  When light falls onto the LDR the resistance drops to a couple hundred ohms and triggers pin 2 high which biases the base of Q1 via pin 6 and R4 and in turn activates the relay __ Designed by Tony van Roon  VA3AVR

7-segment Display Water-Level Indicator -  This water-level indicator uses a 7-segment display, instead of LEDs, to indicate the water level (low, half and full) in the tank.  Moreover, a buzzer is used to alert you of...__ Electronics Projects for You

8 Hints for Better RF Signal Generator Measurements -  Application Note__ Aligent

8 Hints for Making Better Spectrum Analyzer Measurements -  Application Note__ Aligent

8 LEDs Make a 100-Division Voltmeter -  09/22/11  EDN Design Ideas:  Use a counter IC to drive two sets of four LEDs.  The circuit in this Design idea makes a voltmeter that reads to 0.99V.  The idea uses a counter IC to drive two sets of four LEDs (Figure 1).  Each of these two sets represents a BCD (binary-coded-decimal) value.  With all of the LEDs off, the voltmeter reads 0V.  With all of the LEDs on, the reading is 0.99V.  Op amp IC 1A generates a predictable voltage ramp. __ Circuit Design by Raju Baddi, Tata Institute of Fundamental Research, Pune University, Maharashtra, India

8 Stage LED VU Meter -  The circuit below uses two quad voltage comparators (LM339) to illuminate a series of 8 LEDs indicating volume level.  Each of the 8 comparators is biased at increasing voltages set by the voltage divider so that the lower right LED comes on first when the input is about 400 millivolts or about 22 milliwatts peak in an 8 ohm system.  The divider voltages are set so that each LED __ Designed by Bill Bowden

80 Meter DSB Transmitter -  amateur radio construction projects.   __ Designed by Peter Parker

80188XL Engine Tachometer / Race Computer -  The objective of this project is to design a high speed digital engine tachometer.  This requires the design and development of a hardware and software solution to monitor the status of an engine in real time.  in addition, information relating to the overall health and systems of the vehicle can be displayed.   __ Designed by Stephen Manley-smanley @ nyx.net

8038 Function Generator -  Built around a single 8038 waveform generator IC , this circuit produces sine, square or triangle waves from 20Hz to 200kHz in four switched ranges.  There are both high and low level outputs which may be adjusted with the level control.  This project makesa useful addition to any hobbyists workbench as well __ Designed by Andy Collison

8038 Generator -  IC L8038 signal generator chip, manufactured by intersil.  An improved version, made by Exar corp.  is available (XR8038A).  it can be used to produce three types of waveforms, sine, square and triangle.  The frequency, amplitude and duty cycle can be varied, and selection of waveform is done digitally.  To further reduce the complexity, a 3-to-1 switch may be used in place of the digital selection circuitry.  I made use of the digital selection mechanism because switches available on the market are prone to dirt accumulation and poor contact quality.  Besides, the digital method is a lot cooler! .  __ 

80V Wide Range I2C Power Monitor Simplifies Challenging System Monitoring Tasks -  Accurate monitoring of power is an essential part of a reliable and energy efficient (green) system design.  Measuring voltage and current of low voltage (1.8V to 36V) supplies is straightforward, but higher voltages present additional challenges.  in this video, we will show the LTC2945 wide range i2C system monitor.  This __ Linear Technology/Analog Devices App Note, Mark Thoren Staff Scientist-Mixed Signal Products Mar 20th 2013

82 Meter CW ARDF Receiver -  This page contains updates, feedback and circuit modifications relating to the foxfinder-80 ARDF receiver article that appeared in the November, 2000 issue of 73's amateur radio today.  The design data posted at this site reflects the version used at the 2002 championships in Georgia__ 

89c2051proto Board -  This single sided proto board provides an economical solution for developing and testing the projects around Atmel 20 pin series u-controllers (89Cx051 & AVR).   __ Designed by Wichit Sirichote

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


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