modified 5 years ago

PLZ FIX nand gate and gate

01:46:54

NOT WORKING????   can someone please explain why the NAND Gate is not working? I'm not sure if its hooked up correctly
When you press the switch its supposed to shut off the bottom Led then turn on the top one

published 5 years ago

aaaaa10

5 years ago

Bypass switch

maxmax_66

5 years ago

You would be better off using two logic sources, each connected to the equivalent inputs of your gates. This will also prevent floating components.

Robert_Kidd

5 years ago

EC LED’s default to 2V @ 20mA. As you have a 5V supply you need to lose 3V across a series resistor, R=3/.02=150 Ohm. This prevents your LED’s burning.

maxmax_66

5 years ago

Additionally, your LEDs have an unequal operating voltage. Dial down your gate voltage and the bottom LED to 2 volts then you can adjust the gates for your preferred brightness.

Robert_Kidd

5 years ago

Note: see you have changed lower led to 5V working. Better left at 2V or at least consistent in the circuit.

Robert_Kidd

5 years ago

When an open switch leaves a gate ‘floating’ it’s good practice to put a high value pull-down (or pull-up if required depending on function).

Robert_Kidd

5 years ago

See my solution just posted ‘For Chevy stop’. Simplest way to get NAND is just to invert AND output.

Robert_Kidd

5 years ago

Note: your NAND logic is wrong. You need at least one input low fir a high output.

BillyT

5 years ago

Some good answers here, but remember, one picture is worth a thousand words. http://everycircuit.com/circuit/6394645792423936

Robert_Kidd

5 years ago

Which is exactly what I’ve given. Read above.

Robert_Kidd

5 years ago

@Billy, also your circuit does not perform the required function.

cazon

5 years ago

You just need to pull the logic gates to ground through a resistor

Robert_Kidd

5 years ago

@cazon, your link doesn’t work.

cazon

5 years ago

@chevystop, here’s the fixed circuit link. http://everycircuit.com/circuit/6243680057556992

cazon

5 years ago

@Robert_Kidd thank you I’ve fixed it

Redstone_guy

1 year ago

I see no pulldown resistor, so no, you haven’t fixed it :/

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.