Posted on Nov 29, 2012

This matrix can show the values of two variables, for example, frequency and voltage. The display is a graph made from a matrix of LEDs. The LEDs on each axis are color coded, red for out of tolerance and green for in, fanning a red band around the inner green rectangle. The two input voltages proportional to the functions being measured are presented to the two columns of comparators. The other comparator input is a reference voltage derived from resistor ladder Rl to Rx. The output of each row of comparators is processed with an inverted and an AND gate to allow only one active output for any input value.

Click here to download the full size of the above Circuit.

The LED at the intersection of the active drives shows the relationship of the two inputs. The advantage of this display is the ease in reading, modification, and also its small size. All comparators are LM339 quads.

Leave Comment

characters left:

New Circuits



Popular Circuits

Phantom PS for Microphone
DIY intervalometer for Sony NEX
1 watt PLL portable fm transmitter circuit
Bias supply powers low power Geiger Mueller tube
30mA LED Dimmer
Solar Cell Voltage Regulator
building my own aux circuit car stereo feedback
555-pin chip data and circuit diagrams