DIY Mini Oscilloscope

Build this small oscilloscope. Frequency range is up to 40KHz (25uS full screen) In 4 selectable ranges. Input voltage is between 50mVpp and 50Vpp in 2 selectable ranges. Gain is adjustable between 1 and 100. Accepts AC or DC input . Auto-trigger sweep function to "freeze" the wave display. Free sweep is obtained by setting the potentiometer at either extreme setting. Y-axis adjustment to center the wave. Runs from a 9V battery.

Link to: High-res schematic

Sweep time is adjusted in 4 ranges down to 25uS (40KHz cycle full screen).

Use it to center the wave display.

Input range is 50mVpp to 50Vpp in 2 selectable ranges. Input gain is variable from 1 to 100.

Auto trigger sweep function to "freeze" the wave display. Free sweep is obtained by placing the potentiometer at either extreme setting.

Label the sweep time potentiometer from 0 to 10, and use these charts to read the sweep time ( or frequency ) in the 4 ranges. Do the same for the gain potentiometer.

These are the pinouts for the IC's and the LED matrix. If you substitute the LED matrix, verify the pinout. 7X5 led matrix must be common anode.

When in auto-trigger mode you get these displays sweep time is either too high or too low with respect of the input wave, adjust range/potentiometer.