kkr blogs

  I HAVE MADE DIGITAL ELECTRONIC DICE  USING LOGIC GATES AND BOOLEAN ALGEBRA IN VARIOUS COMBINATION TO DEVELOP LOGIC IN PURELY ANALOG CIRCUIT. WE HAVE USED DIFFERENT LOGIC GATES AND THEIR COMBINATIONS TO OBTAIN THE DESIRED RESULT FOR OUR PURPOSE. WE HAVE MADE AN ELECTRONIC DICE USING A 7-SEGMENT DISPLAY,4026 DECODER IC,555 TIMER,PULSE GENERATION IC AND SOME LOGIC GATES SUCH AS AND GATE AND NOT GATE       THE 4026 DECODER IC IS USED TO DISPLAY THE NUMBERS ON 7-SEGMENT DISPLAY FROM 0-9 ONE BY ONE. WHEN THE PULSE GENERATOR IC (555 TIMER IC) GIVES PULSES TO 4026.  FIRST OF ALL SOME LOGIC IS TO BE DEVELOPED SO THAT THE DECODER IC RESETS AFTER THE NUMBER 6 BECAUSE A DICE CONTAIN NUMBER UPTO 6.  WHEN THE LOGIC IS DEVELOPED WE WILL BE SUCCESSFULL IN MAKING THE 7-SEGMENT COUNT FROM 0-6 ONLY.       AFTER THAT IF WE HAVE TO STOP THE DISPLAY AT A PARTICULAR NUMBER SO THAT THE PLAYER GETS A NUMBER TO PLAY.          WORKING OF A SIMPLE 7-SEGMENT DISPLAY                      

This is an automatic night lamp circuit diagram, made using a pnp transistor, a dark detector Here ldr is light dependent resistor, p1 is a potentiometer (100kohm-500kohm). and the pnp transistor is working as a switch in this circuit. Consider the following diagram to  understand the functioning of pnp as a switch. We can also use PNP transistors as switches, the difference this time is that the load is connected to ground (0v) and the PNP transistor switches power to it. To turn the PNP transistor as a switch "ON" the Base terminal is connected to ground or zero volts (LOW) as shown.