74LS08 IC is a member of 74XXYY IC series. There are four AND gates in the chip and each gate have two inputs, hence the name. 74LS SN74LS08NSR. ACTIVE. SO. NS. Green (RoHS. & no Sb/Br). CU NIPDAU. LevelC-UNLIM. 0 to 74LS SN74S08D. ACTIVE. Note The ”Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaran- teed The device should not be operated at.

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If you do use a pull down resistor, make it low like PeterBennett recommended. For better understanding the internal working let us consider the simplified internal circuit of AND gate as shown below.

74LS08 – Quad 2-In AND Gate

I have tried switching to a 9v battery and nothing anf. There are four legs connected together in pair of two. Sign up or log in Sign up using Google.

The circuit working can be explained in few stages below: I am new to electrical engineering still so forgive me if I am making a 74ls0 mistake. At this time the total VCC appears across resistor R1. When both buttons are not pressed. Post as a guest Name. Looking at the image I agree. Because output is nothing but voltage across resistor R1 it will be LOW.


74LS08 Datasheet

Email Required, but never shown. The inputs with both switches unpressed allow the pins to float around, depending on the way the IC is set-up internally. 74ld08

In this state the current flow through base of both anc will be zero. There are four AND gates in the chip, we can use one or all gates simultaneously. The chip is used in systems where high speed AND operation is needed. Sign up using Facebook. The two inputs of AND gate are driven out from bases of the two transistors.

74LS08 – Quad 2-In AND Gate

The inputs of the 74LS family and other TTL versions source significant current and will appear as a logic High unless firmly pulled to Ground – your k resistors won’t help. Pressing the buttons does nothing. I think that you were dead an in the first place with your answer SaraHeart.

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With the LS you need to sink 1. And after a google search I havnt come up with anything, usually the videos are terrible quality or they are using a different AND gate. Something similar should be an to the right button. They are notorious for that particular mishap. Pull down resistors as suggested in another answermight also a good idea. 74s08 of the AND gate is the voltage across resistor R1.

Home Questions Tags Users Unanswered. The switch between the input 74ls0 and Ground will provide a Zero Ohm connection to Ground when the switch is pressed, ensuring that the gate sees the input as a Low. It is really popular and is available everywhere. TL — Programmable Reference Voltage. Both transistors will be ON and voltage across both of them will be zero.

With that the drop across resistor R1 will be zero. It might be oscillating as well. After verifying the three states, you can tell that we have satisfied the above truth table. A few mentioned below.