trouble with not (inverter) gate

Hi.

I am trying to invert digital signal from arduino. I connected original signal to led and it is on ok. Then I connected signal to SN74LS05N, but output is always LOW.

I connected ic according to instructions. Am I using wrong series? Is SN74LS not compatibile with Arduino. Is there an example how to connect not gates? (or and gates or or gates)

br,ivan

The 74LS05 is an open-collector output. You need to use a pull-up resistor with the output of the gate.

(This is different from a 74LS04).

Which series is the simples to work with Arduino? 7400? I just need a couple of not gates,flip-flop and maybe and gate and or gate.

ivanb: Which series is the simples to work with Arduino? 7400? I just need a couple of not gates,flip-flop and maybe and gate and or gate.

The series isn't the problem. The 74LS[u]05[/u] happens to be an open-collector NOT gate. A 74LS04 is a "standard" inverter.

I wouldn't call the open-collector "difficult to work with" or "incompatible with an Arduino." You just add a pull-up resistor to the output of the inverter. That's pretty simple.

Forget old TTL logic series like LS, that technology is 1/3 century old! 74HCXXX is the series to choose (or for analog/digital interfacing at higher than 5V sometimes the 4000 series - but they are slower). 74HC series ought to be cheaper and easier to get hold of too.

Forget old TTL logic series like LS, that technology is 1/3 century old!

Yes but so am I and I still work. ;)

74HC series ought to be cheaper

It is not always.

and easier to get hold of too.

Now that is where you are wrong, I have got lots of them in my component draw, you can't get easier than that.

There are some disadvantage with the HC series like lower noise immunity caused by higher impedance inputs, although that can also be and advantage in some situations.