Milli Volt Source for Printer Port

This circuit uses a R-2R Ladder Resistor Network to convert digital data from PC Printer Port to Analog. This can be used as a Millivolt Source or Programmable Power Supply.

This circuit is a R-2R, Digital to Analog Converter. You can replace the R2R with a D-A Chip for better performance. This circuit is just to understand the Concept, for learning and Experimenting.

Milli Volt Source for Printer Port

Milli Volt Source for Printer Port

The MFR resistors are 1%, hence the precision of this Conversion is not very good. It is ok for servo applications or closed loop conversion along with the ICL7135. That can be tried with software.

A 4053 Analog Switch controlled by PC software will give you a negative or positive output. R41 trimpot is to calibrate or scale output. If you modify this circuit, you could output data at a fast rate, then you have a staircase generator. You can write software for a waveform generator or function generator too.

You can design a dual tracking power supply over this. You can loop it with the DVM circuit shown earlier and make a 12 bit accuracy millivolt or milliamp source. It will depend more on the software and little addons to circuit.

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