SN54/74LS QUAD 2-INPUT AND GATE. LOW POWER SCHOTTKY. J SUFFIX . CERAMIC. CASE N SUFFIX. PLASTIC. CASE 1. 1. Symbol. Parameter. DM54LS DM74LS Units. Min. Nom. Max. Min. Nom. Max. VCC. Supply Voltage. 5. 5. V. VIH. High Level Input. 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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Because of this the chip can be used for high speed AND operations. They are notorious for that particular mishap.
I am new to electrical engineering still so forgive me if I am making a stupid mistake. In that case, the left button should have a red wire on the lower left pin.
You might be using push buttons that are connected in such a way that the legs are shorted connected together. Because total VCC appears across transistors the drop across resistor R1 will be zero. Next Article Timer IC. If you choose the wrong pair, you end up with an always on switch. 7ls08 Questions Tags Users Unanswered.
At this time the total VCC appears across resistor R1. Both transistors will be ON and voltage across both of them will be zero. In the circuit two transistors are connected in series to form 74ls088 AND gate. As AlmostDone said, you need to draw about 1. There are four legs connected together in pair of two.
Then if your IC is good your switches are mis-wired, I have done it myself with that type of switch. 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. You could try adding a pull down resistor k, K, ohm, doesn’t much matter your inputs may be floating high. Looking at the image I agree.
The 5K1 pull-up resistor ensures that the pin is seen as High when the switch is not pressed. It is currently powered by a 5v 1. The inputs on CMOS parts anything with a “C” in the middle source or sink very little current, so K pull-up or -down will work with them.
Pull down resistors as suggested in another answermight also a good idea. The four AND gates in the chip mentioned earlier are connected internally as shown in diagram below. It might be oscillating as well. Sign up or log in Sign up using Google.
74LS08 Pinout, Configuration, Equivalents, Circuit & Datasheet
Simon Marcoux 1, 2 Sign up using Email and Password. The inputs with both switches unpressed allow the pins to float around, depending on the way the IC is set-up internally. It is really popular and is available everywhere. When any one of the buttons is pressed. Top menu About Us Contact.
Sara Heart 1 6. This LED is connected to detect the state of output. For better understanding the internal working let us consider the simplified internal circuit of AND gate as shown below.
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74LS08 – Quadruple Two Input AND Gate
Because output is nothing but voltage across resistor R1 it will be LOW. The two inputs of AND gate are driven out from bases of the two transistors.
I think that you were dead 74ls088 in the first place with your answer SaraHeart.