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Simple Test Equipment 

• High Resistance Indicator.
  
• Digital Potentiometer.
• Function Generator using ICL8038.
  

More Designs

• Auto ranging 4-1/2 Digit Digital Voltmeter
• 3-1/2 Digit ICL7107 Digital Panel Meter
  
• Dial AVO meter

I am listing some basic circuits here to build a Hobby Workbench. Test Instruments and Tools for the Hobby and DIY People. Troubleshoot projects that have become unresponsive.

The circuits above are in html format with the circuits in jpeg within the pages, but may not be complete, but you may get ideas, i even don't remember if they worked properly.

Electrometer, Gauss Meter and EMF Meter

In the digital potentiometer, connect pushbutton switches to fast and slow with one end to +7.5V, when you hold the button down the analog voltage will ramp up-down, fast or slow, this will enable you to make a digitally controlled millivolt source or power supply.



I did make a  millivolt source with this and it still works after 15 years. Some ideas used in this i got from a magazine elektor and some learning i got from another mag Radio Electronics.

Amp Hour Meter using LM331 and 74C926

Nixie Tubes were the Earliest form of Digital Displays, Electromechanical Counters also had Numerical  Displays and Clocks made from that. Nixie came later and was used in Early Frequency Counters and Multimeters. A Direct descendent of this was the Vacuum fluorescent display.

OscilloScopes for the DIY Enthusiast 

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Vacuum fluorescent display in VCR

Some may Remember the Very Old Texas Instruments Calculators with Hard Clicking Keys. They had these Displays too. These are very Bright and Visible in Sunlight too. A Pleasure to watch.

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More Enchanting Nixie Tube Images

                           

Nixie clock made by an unknown enthusiast. I put it here as it is very impressive and nostalgic too