Test-Measurement

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This indicates like LM3914 in dot-mode. It is a drawing i made made to troubleshoot a gadget, around two decades ago. Strangely it had a echo of a design i had made into a 7107 dpm years before that. Now i am scanning all my drawing and notes, useful or not. Clean or with errors. Many Errors = 1 Blunder. Some projects i made have been expensive Blunders. So see them with a skeptic eye, fix them, try them. Thats all for now.

See the Circuit Full Size – Microohm Meter with LED Analog Bar

Microohm Meter with LED Analog Bar

This has a 9V battery power. The 555 spins and a negative voltage for Opamp is created. This is a Low Offset amp of OP37 of Precision Monolithics, Inc PMI an early innovator. This diff-amp amplifies the uV of a 4 wire resistance measurement.

Now the current pump is the 2N2222 you see above the OP37. The FET and 555 do synchronous rectification. The LM324 is the Indicator and Analog to LED Dot-Bar Converter. The probes are Gold Plated, or use solid gold pins if you have them in plenty.

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“Bluetooth Multimeter is an intelligent peripheral of android phones, specially designed for engineers. Not only can it easily collect data such as voltage, current and resistance etc., this multimeter can also communicate with phones via bluetooth. Thus, the data gathered will be displayed on your phones.”

Bluetooth Multimeter – Seeed Studio

Totally open source, including hardware, software & Android API. Learn how to create a Platform to connect smartphones with the real life.

Bluetooth Multimeter - Seeed Studio

The Bluetooth Multimeter is based on Atmega328 – Arduino Pro. It measures the voltage and resistance and current input from the headphone jack, and then sent these data via the Bluetooth frame.

Android UI for Bluetooth DMM

This Bluetooth Multimeter is a portable multimeter, a device that gathers the voltage, resistance and current. and then sent these data to other device via Bluetooth, so, we could display the data through other devices, such as Android, PC and so on.

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In: Hobby Lab, PC Computers
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Zelscope is a Windows software that converts your PC into a dual-trace storage oscilloscope and spectrum analyzer. It uses your computer’s sound card as analog-to-digital converter, presenting a real-time waveform or spectrum of the signal – which can be music, speech, or output from an electronic circuit.

Zelscope Sound card oscilloscope

Zelscope features the interface of a traditional oscilloscope, with conventional gain, offset, timebase, and trigger controls. As a real-time spectrum analyzer, Zelscope can display the amplitude and phase components of the spectrum.

Zelscope Sound card oscilloscope

The typical input voltage should be about 1 volt AC at the line-in jack of the sound card, so a voltage divider or a buffer amplifier is highly recommended.

xoscope for Linux –  Similar Ptoject

Zelscope also allows for an easy measurement of short time intervals in mechanics experiments. Zelscope has proven useful in debugging music and sound processing software.

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Here are some Hobby Scopes that might even be quite professional if you develop them further. They are virtual instruments. Making Scopes with tablets may be much more easy now.

The µSCOPE – A poorman’s oscilloscope
The oscilloscope is still one of the most important measurement tools of the electronic engineer. With the advent of the often very reasonably priced USB scopes, such an instrument is now within reach of every body.

OscilloScopes for the DIY Enthusiast

Digital oscilloscope – Build a simple Inexpensive digital oscilloscope. Single channel, about 100 MSPS. RS-232 based.

xoscope is a digital oscilloscope using input from a sound card orEsounD and/or a ProbeScope/osziFOX and will soon support Bitscopehardware. Includes 8 signal displays, variable time scale, math,memory, measurements, and file save/load.

xoscope – digital oscilloscope for Linux

MHZ100Q is a low cost FPGA-based high speed data acquisition system. Version 2 is a standalone board containing 2, 100MHz 8-bit A/D channels, preamp, 7th order elliptical antialiasing filters, and a Xilinx FPGA.

MHZ100Q – Open Source FPGA-based 100MHz A/D

A USB interface is implemented in the FPGA firmware. Power comes from the USB bus. Schematics, VHDL and Verilog source code, and signal capture and display software are available and being posted.

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DSO Nano v2 is an Open Source Portable and lightweight Digital Storage Oscilloscop that has a Color display and is designed for basic electronic engineering tasks. Its palm size and handy features make it great for in-field diagnosis, quick measurement, and hobbyist projects. Schematics and source code files are also openly available for re-innovating.

DSO Nano –  Digital Storage Oscilloscope

Auto measurement – Useful for quickly exploring signal characteristics. Measurement options include frequency, cycle time, duty cycle, peak voltage, RMS voltage, average voltage and DC voltage. Please note that frequency, cycle time and duty cycle can only be measured while triggering.

DSO Nano - Digital Storage Oscilloscope

Features – Waveform storage and playback, 6 triggering modes, 200Khz Analog Bandwidth, Complete measurement markers and signal characteristics. Built-in Signal Generator too.

User Interface Overview – The screen is broken into a central display area and 3 operation bars around it. The menu on the top provides the most frequently-used adjustments to signal display. The status bar on the bottom provides precise measurement results and monitoring status. Adjust more advanced functions with the column of function icons on the right.

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An android virtual instrument – OsciPrime is an Open Source Android high speed data acquisition hardware platform and Android oscilloscope application.

Open Source Android Oscilloscope

Open Source Android Oscilloscope

Using USB, the hardware plugs into Android devices that support USB Host. Together with the OsciPrime Android oscilloscope application it turns a tablet or mobile phone into a high speed data acquisition system.

Android Scope

OsciPrime Oscilloscope Android App

Hardware Specs:

  • 2x Analogue Input @ 8bit/6Msps
  • 5 analogue gain levels
  • 3.3 MHz – 8.0 MHz Bandwidth (gain dependant)
  • 16 V Max Input Voltage
  • 880 mW Power Consumption
  • Designed for 10x Probes

The Android App Instrument Performance and Controls Include

Controls -V-Offset, Time-Offset, Calibration; Trigger Controls Falling/Rising and Edge, You can Measure Voltage, Freq and Period.

  • Range +/- 1.5 V up to +/- 16 V
  • 5 us/Div max – 1 ms/Div min
  • Processing 400’000 samples per second

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History and accomplishments of the General Radio Company, one of America’s first equipment manufacturers for the radio and electronics industry.

General Radio Historical Society

Founded in Cambridge, Massachusetts in 1915, GR provided the tools and instruments that allowed the electronics industry to burgeon into today’s giant that fills our lives with radio, TV, computers, cell phones, DVDs and all the other electronic products in our homes, businesses and automobiles.

General Radio Experimenter

General Radio Experimenter

This pioneer publication first appeared in June 1926 and became the model for many others to follow (most notably the HP Journal). It began with engineers talking to radio amateur customers and gradually changed to engineers talking to other engineers, who might also be customers.

GenRad 1863 Megohmmeter

GenRad 1863 Megohmmeter

The GenRad 1863 Megohmmeter is the choice for production and inspection tests on devices with resistances up to 20 Tohms.

Read more at my EEMetric Genrad Wiki Stub

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This is an interesting attempt in the right direction. The bandwidth may be only the audio range, but the first instruments with touch interface for tablets are being built for tablets even by DIY Enthusiasts.

SpecScope from NFX Development

SpecScope is a spectrum analyzer and is the second in the line of engineer applications from NFX Development. The SpecScope incorporates the speed and ease of use to access FFT frequency measurements in a hurry.

Some of the Features

  • Logarithmic/Linear measurements
  • Pinch to zoom in both X and Y axis
  • Selectable No. bin for accuracy versus speed
  • Three settings of spectrum averaging
  • Threshold trigger to hold the peak value
  • Tap to pause and resume measurements (graph is still navigational in this mode)
  • A adjustable sample rate allow analysis from 10 Hz to 22KHz