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Build a DMM or Digital Multi Meter

• LM3914 Analog display Resistance.
  
• 3-1/2 digital display for +/- 199.9mV.
• Power supply, battery backup for DMM.
• DMM range, AC-DC mode, logic control.
• AC conversion, continuity buzzer test.
  
• Voltage measurement attenuator amp.
  
• Current Shunt Amplifier digital control.
  
• Resistance measurement Current Source.
  
• Analog Buffer, Inverter Switching logic.

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The indispensable Digital MultiMeter DMM:

Moving Coil Voltmeters, Ammeters and Resistance Bridge were combined to make AVO Meters a field instrument. They were used alongside hand cranked meggers, current-potential transformers. Valve based Electronic Instrumentation with Nixie Tube Displays cannot be forgotten, taking readings from nixie tube displays can be more satisfying than reading a plain LCD. The Vacuum Florescent 7 segment display array was popular till very recent times in some cash registers, calculators.

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DMM or Digital Multi Meter

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Then came Semiconductor Transistor Multimeters with a Moving coil display, after that arrived LED Display based Benchtop Semi-Portable DMM, which were "IC" Technology.  These consumed more power and big in size. Now you have CMOS, LSI and ASIC based DMM which are light, small and batteries last longer too.

Bluetooth Multimeter

PC based Virtual DMM, Voltage modules for PLC or ATE and Wireless or optic Voltage Transmitters are new and advanced form of Electrical Parameter Measurement and Recording.

Source Files for above DMM Project 20008.zip,  20009.zip,  20010.zip,  20011.zip,  20012.zip,  20013.zip,  20014.zip,  20015.zip,  20016.zip.

• Auto ranging 4-1/2 digit digital voltmeter 
• ICL7135 to Printer port 4-1/2 DVM.
  
• Milli Volt Source for Printer Port.