Part Number: 74LS, Maunfacturer: Motorola, Part Family: 74, File type: PDF, Document: Datasheet – semiconductor. These 8-bit shift registers feature gated serial inputs and an asynchronous clear. A low logic level at either input inhibits entry of the new data, and resets the first. This 8-bit shift register features gated serial inputs and an asynchronous reset. The gated serial inputs (A and B) permit complete control over incoming data as a.

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Is that a good thing, or a bad thing? Since the IC is a relatively bad conductor right? You could add 2 or 3, 22nF’s in place of the nF. Since I am still a bit confused about the whole pull-down and pull-up thing I have read about it, but it still didn’t really sink inI tried the following: For a better experience, please enable JavaScript in your browser before proceeding.

My problem is that nothing seems to work, and, even daatasheet Functional operation should be restricted to the Recommended Operating Conditions. The gated serial inputs A and B permit complete control over incoming data as a low at either or both input s inhibits entry of the new data and resets the first flip flop to the low level at the next clock pulse.

You can see a photo of datwsheet circuit which I hacked together according to various pretty pictures I found online here: Just one last question i hope: I googled around, and most of the internet seems to agree that a pull-up and pull-down resistors are nice and all, but shouldn’t really be an absolute necessity for a simple thing like this and, I don’t quite ‘grok’ them b I was afraid that I somehow fried my ICs, but noone else seems to have a problem connecting them directly to their power supply.

High Level Output Current.

Datasheet «SN54/74LS164»

But in this case, I’d be pulling up an output pin, and the input of the second IC would always be ‘on’ by default. I already had the circuit soldered, and being the stubborn guy i am and because of my lack of solder-removal-wickI tried it with pull-down resistors 1k to GNDagainst all recommendations i read online.


Welcome to our site! All inputs are diode- clamped to minimize transmission-line effects. The 22nF are for the switch contacts, to eliminate any electrical noise, caused by switch contact bounce.

74LS 8-bit Shift Register IC | Jaycar Electronics

If I have a shared clock signal datsaheet both the ICs which seems to be a common praticeAs stated when inputs are connected to output pins, NO pull ups.

I do understand that the pull-ups and -downs would be ‘good engineering’ – but may I have your blessing not to put in the capacitators, this being a purely experimental thing? To participate you need to register. If I look at the construction in the wrong way, it often triggers the signals.

Datasheeet have this lingering gut-feeling that I there is something very basic that i am not understanding That didn’t nudge the 1. So, my next iteration of this thing is definitely going the pull-UP route.

When I switch on the lights in my house, this often triggers the signals. Functional operation should be restricted to the Recommended Operating Conditions. I’m a software guy, who is now trying to get a little bit into circuits, just for fun.

Low Level Output Voltage. Fully Buffered Clock and Serial Inputs.

74LS164 Datasheet PDF

The IC is a shift register so it does effectively have a latch function, any data in the SR is stored until the power is removed or its clocked out Hence, the input of my second IV would be high all the time thanks to the soon-to-be soldered pull-up.

Low Level Input Current. So when you push the switch the ‘A’ pin goes low and when you release the switch the ‘A’ pin goes high, giving a high going clock edge which is whats required by the LS Or am i maybe measuring the voltage in a wrong way?


The IC is very fast so you will [ or shouldn’t] see any flicker as the SR clocks. I think I understand the function of the capacitators de-noising, by functioning as a little ‘buffer’ of sorts, right? There could be any number of reasons why its not working, follow my instructions and we may find out why. Datasheet for the 74LS But with the inter-IC connection, I think my brain is still not in gear: Read the above entry d it seems that the LS type ICs are famous for their floating voltages and sensitivity – is there some other type of IC that might be 74ls1164 forgiving for a beginner?

A high level input datashret the other input which will then determine the state of the first flip-flop.

74LS (SLS) – 8-bit Serial-input/parallel-output Shift Register | eet

What is the standard way of doing this? Didn’t help at all. Thank you two for the quick reply. By continuing to use this site, you are consenting to our use of 744ls164.

All inputs are diode- clamped to minimize transmission-line effects. You need pull downs on both your push buttons. Forums New posts Search forums. Low Level Output Current. This site uses cookies daasheet help personalise content, tailor your experience and to keep you logged in if you register. Electro Tech is an online community with overmembers who enjoy talking about and building electronic circuits, projects and gadgets. Thank you again for any help! Thread starter schweini Start date Nov 16, If I understood the datasheet’s diagram correctly, there’s an AND gate on the two input pins, so I think both have to be high – but that doesn’t really matter, since I simply connected the two together.

Propagation Delay Time, Reset to Q. Setup Time, A1 or A2 to Clock.