Hi, I was just wondering, why is the nand gates (used as an ocillator) in the circuit below have its inputs shorted together? wouldn't they function as inverters? if so, why did the circuit maker use nand gates instead of NOT gates if he will make the nand gates function as inverters? Please reply.

 

You are correct. The NAND gates are wired as inverters.The designer could have chosen NAND gates or inverters. I was going to say it is six of one and half a dozen of the other... more like six of one and four of the other.

BTW. What is not shown in the diagram is the practice that all unused inputs must be connected, perhaps to GND.

 

Thanks for the reply.

i have another question.

what if i use the circuit below

and remove the nand gate oscillators for the piezo buzzer so it would look like this

will there be any undesirable effect in the circuit aside from the fact that i have no piezo buzzer to produce an audible sound after the 4017 stops its inputs and stays in one LED?

 

I am not quite sure what is the objective of the circuit.

 

it says in the website i got it from, that the NAND gates function as oscillators that feed clock pulses to the 4017 input pin.

It's a random number generator.. or you can call it LED roulette too. When S1 is pressed, the 4017 starts its sequential outputs until the C2 discharges completely and make the 4017 stop to a random LED.. That's how i understand it. :|

 

Ok, I get it now. It is a roulette circuit and the beeper makes a tick every time the wheel advances. So you have removed the beeper and just let the lit LED move around. I see nothing wrong with that.

 

Thanks for the reply THANKS A LOT MrChips

 

An oscillator is an oscillator is an oscillator. If it has the proper output signal to interface to your load it will work whatever kind it is.