SN54/74LS • SN54/74LS • SN54/74LS DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified). S. b l. P. 74LS Octal Buffers AND LINE Drivers WITH 3-state Outputs SN74S, SN74S OCTAL BUFFERS Details, datasheet, quote on part number: 74LS Texas Instruments 74LS Buffers & Line Drivers are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for Texas Instruments .

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Texas Instruments discusses some of these results of reduced voltage power supply voltages to ICs, in this short ” Designing With Logic ” document. Which I have interpreted as being: A tristrate output can have 3 different states: I was wondering if I didn’t have broke my chip because I don’t have protected the input gate, 74s241 it wasn’t asked in the schema. Your explanation “two input are high” datasheft more like the definition of an AND gate.

And we still don’t know how you have your LED connected???? A 74LS or any 74LS family part will normally see an unconnected input as a High – you need to connect inputs directly to Ground to input a Low.

74LS 데이터시트(PDF) – Motorola, Inc

Email Required, but never shown. Then i wired the 19 and 17 pin with 3. Pull pin 19 high, and the output will follow the input 17 and either the green or datasehet red LED will glow brightly; the other one will be off.

I don’t use the two G inputs at the same time. It is not guaranteed to operate at 3.

So here is what I did: Understanding how a tristate buffer works 74LS Ask Question. Do you have 5 volts Vcc connected to pin 20, and have pin 10 grounded? But my led at pin 18 just glow dimly and datasheft change state, no matter if pin 2 is high or not connected. When you connected [3. The LED being lit is not a surprise. Do you understand what a buffer is and why we use it? I didn’t put any resistors on the input.


Please show the schematic diagram. Therefore it is also no surprise that when you did connect pins 17 and 19 to Vcc, the LED stayed lit. For some reason, this isn’t working on my circuit. In the first two instances the output is actively pulled low or high using a transistor; in the disconnected state, neither transistor is activated.

74LS241 Datasheet

Why is my microcontroller passing a current through it when not connected? Sign up using Facebook. Without it, the outputs float. So I clearly don’t understand at all. And when I connect the Vcc pin, without 19 and 17, my led is on, where I expected this to be off. This will also cause behaviour which is different from the behaviour when correct power is connected.

If you use a 5V power supply, and make sure this is always connected to the device Vcc and Gnd pins see belowthen you should see expected behaviour.

744ls241 And when I connect the Vcc pin [ I would have guessed the current gain was more than 0. But I thought gate like those didn’t need to be protected. Therefore any results you get using a power supply of 3.

And if I’m connecting pin 19 and 17 to be high, I’m expecting that my led will be brighter, but it just glow dimly, no matter if pin 17 is high or not connected. Post dafasheet a guest Name. Then [you connected 3. Sign up or log in Sign up using Google.

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By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. I’ve done quite a lot of research since first writing this answer, and with unpowered 74LS devices and an input voltage between 0 V and 5.

I have put a dataxheet on the 3 output pin, in order to test the output. Another issue I’ve observed is parts that behave as though pairs of pins are connected via PNP transistor, such that excessive voltage on one will cause the device to source current into the adjacent pin.

74LS datasheet, Pinout ,application circuits OCTAL BUFFERS AND LINE DRIVERS WITH 3-STATE OUTPUTS

Sign up using Email and Password. Pins 1 and 19 of the LS control this state for the buffers inside the chip.

Do you understand WHY we have tri-state outputs? Mr Bonjour 1 2 MrBonjour Try another gate then. SE topics where powering devices via other pins, instead of the power pins, caused unexpected behaviour: By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Note the invertor symbol tiny o ring at the control gate connected to pin 1; you must pull pin 19 high to activate, and pin 1 low to activate. Which Datzsheet have interpreted as: I was expecting that my led will be off with pin 17 not connected but pin 19 still high, and the led on with 17 and 19 high, but this is not happening. JvO 2