555 Counter Timer UP and DOWN

Fully functional from 00->xx and xx->00 Semi digital UP and DOWN timer realized with a relay. Bi-directional Switches: ON OFF DIGIT ONE MANUAL UP DIGIT ONE MANUAL DOWN DIGIT TWO MANUAL UP DIGIT TWO MANUAL DOWN OPTION AUTOMATIC UP DOWN IMPULS 555 ON OFF (pause) SERVICE: Turn off the Impuls tap switch first. Turn on Power and the white Bulb goes on and set up device using up and down taps for each display. Choose up or down counting with that option switch. Turn on 555 impulse switch and get rapid balls rolls... The white bulb shows the 555 is turned on and the blue LED indicates the Impulse rate. The four tap switches set up count down / up. The red LED indicates that BOTH displays show ZERO and the relay turned on and did cut off main current supply or Impulse (Slight alternation necessary!) so the device stops by completing ONE cycle while count down. A new set up will be required by means of the taps. Up count is one cycle too. There are only two kinds of logic gates necessary (AND and XNOR) to pass on the correct decimal bi-directional count sequence and turns on the red light and the relay as soon both displays expose zero...that's it! ! Dig it! This circuit sure is the best and reliable timer available to public on this platform. 💥💫👍👽👍🌟✨💢

published 11 years ago