Precision Amplifier with Digital uC Control

 Embedded-Systems, Opamp-Circuits, Test-Measurement  No Responses »
Dec 152008
 
Precision Amplifier with Digital uC Control

When Instruments are designed a analog front end is essential and also as most equipment have digital or microcontroller interface the analog circuit needs to have digital access. The Circuits DACT0008 and DACT0009 are both useful in building instruments which have digital control. This circuit DACT0009 is similar to DACT0008 but gains of upto 100 can be realized in this configuration, this is useful for signal conditioning of low mV outputs of transducers. The gain selection resistors R3 to R6 can be selected by the user and can be anywhere from 1K to 1M and can also be trimpots for Read More …

 Posted by admin at 4:45 AM

Precision Attenuator for Digital uC Control

 Embedded-Systems, Opamp-Circuits, Test-Measurement  No Responses »
Dec 102008
 
Precision Attenuator for Digital uC Control

When Instruments are designed a analog front end is essential and also as most equipment have digital or microcontroller interface the analog circuit needs to have digital access. The Circuits DACT0008 and DACT0009 are both useful in building instruments which have digital control. Precision Attenuator with digital control The Circuit DACT0008 is a programmable attenuator and the digital control can be a remote dip switch, a CMOS Logic Output like the A-B-C-D outputs of a decade counter, or an I/O port of a uC like 80C31. The heart of the circuit is the popular OP07 OpAmp with Ultra Low Offset Read More …

 Posted by admin at 6:25 PM

Measureall Workbench Test Instrument

 Test-Measurement  No Responses »
Sep 042008
 
Measureall Workbench Test Instrument

This was a Student Project of mine, it is a very basic instruments that could do most of the tasks on a test bench. The cabinet used, was available as a part of a Hi-Fi DIY System, The Range and Mode switches were Modular Stackable Interlocked MultiPole Switches. The rest of the Interface were wirewound pots, jacks, sockets and plugs. The front panel was Engraved Acrylic, the panel was the toughest issue we tackled. I wanted it to look well engineered, at least on the outside. It was a total analog instrument except for the digital indication of ICL7107. Thanks Read More …

 Posted by admin at 12:00 PM  Tagged with:

3-1/2 Digit ICL7107 DPM Digital Panel Meter

 Test-Measurement  No Responses »
Aug 022008
 

This is a Digital Panel Meter based on ICL7107. This was the workhorse Digital Readout chip before Low power uC designs were developed. Even now it is the easiest way an analog parameter can be displayed in an instrument. 3-1/2 Display is just enough resolution for recording process data or troubleshooting equipment. With 4-1/2 you notice the problems of thermoelectric EMF of probes and connectors. That is one reason gold plating is used another being low contact resistance. In 4 1/2 the reading can change due to contact resistance too, if the input impedance of the analog signal conditioning is Read More …

 Posted by admin at 7:51 AM  Tagged with:

Temperature Calibrator Milli Volt Source

 Test-Measurement  No Responses »
Jul 022008
 
Temperature Calibrator Milli Volt Source

This is a Milli-Volt and Milli-Amp Source for Calibration of Temperature Measurement and Control Instruments using Thermocouples. There is also a Passive Variable Resistance Source for Simulating a PT-100 RTD Sensor. This calibrator was a simple solution i built. This instrument itself was calibrated by Instruments like the Calibrators from Omega which are the best you can get. Related Resources – Temperature, Thermometer, Thermister and RTD Calibrator Cole-Parmer Catalog – Calibration Equipment Temperature Calibration in Industrial Processes Martel Calibrators – Temperature Calibrators Thermocouple Calibration Furnace Thermocouple Simulator-Calibrator

 Posted by admin at 6:28 AM

Transistor Beta and Vce Tester

 Test-Measurement  No Responses »
May 032008
 
Transistor Beta and Vce Tester

This was a Beta Hfe and Vce Measuring Instrument used in Incoming Inspection of Power Transistors made by me 16 years back. Related Resources – Testing Transistors with Ohmmeter The Transistor Curve Tracer Transistors as current amplifiers Transistors Tutorial Transistors – The Electronics Club Basic Testing of Semiconductor Devices Full Featured Transistor Tester This post was created by dapj Web

 Posted by admin at 8:27 AM  Tagged with:

Tera Ohm Meter and Insulation Tester

 Test-Measurement  No Responses »
May 022008
 
Tera Ohm Meter and Insulation Tester

This is a 20 Tera Ohm Insulation Tester I made around 20 Years Back. It had even Polarization Index for Transformer Insulation. It generated 1000V DC Regulated Voltage and the pA leakage Current was Measured. See more here Insulation tester or Tera ohm meter. A regulated, low ripple, high voltage of very low current capability is applied by instrument on a DUT (device under test). The leakage current in nA or pA (picoamps, nanoamps) is measured and readout, The Innovation i did was to measure the current in Vref and not Vin of ICL7107, this made the 1/x computation. Also Read More …

 Posted by admin at 5:04 PM  Tagged with:
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