My nixies & nixie clocks, Blue & White 7-segment LED Clocks, PIC16F84 based Dark Room Timer, PIC16F876 based 2-channel Electronic TL-Dimmer.
Low drop Temperature Controlled FANregulators with LM2941CT & LF356. Digital Flowmeter for SwissFlow flowsensor. 15V – 7A PWM Speed Controller with NE556 & N-MOSFET for minidrill.
This schematic is ment to digitally display the output of my electronic Swissflow SF800 flow sensor. This sensor puts out an open collector square wave signal (like a fan RPM monitoring signal) between 50Hz (=0.5 liter/minute) and 2000Hz (=20 liter/minute). By dividing the measured frequency by 10 and putting the decimal point at the right place you get directly a display in liter/minute.