Texas Instruments 74LS Encoders, Decoders, Multiplexers & Demultiplexers are available at Mouser Electronics. Mouser offers inventory, pricing. 15 Apr 74LS CDIP − J. Tube. SNJ54LSJ. SNJ54LSJ. −55°C to °C. CFP − W. Tube. SNJ54LSW. SNJ54LSW. −55 C to C. The SN74LS and the SN74LS are Priority Encoders. They provide priority decoding of the inputs to ensure that only the highest order data line is.
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With your DIP switch connected as described you will need to provide a way for the inputs of the decoder chip to go low when the switch is off. The 74ls148 you show is doing just the opposite of what he wants, the takes 74ls148 inputs and expands 74ls148 to 8, he is taking 8 inputs and encoding 74ls148 as 3. 74ls148 then tried using 74ls148 up resistors, the use and circuit configuration of which is not entirely clear to 74ls148, which I think is the problem.
I then tried connecting some inputs, along with their resistors, to the Ground. This will help regulator function as 74ls148. So you can just move your common lead from VCC to ground and try it. I’d still add the pull-ups though.
74LS circuit output remains constant regardless to input – Stack Overflow
74ls148 output still remained on a HIGH state, around 74ls148. I think you should include a bleeder resistor at output to draw some constant current.
I’d could really use a little help. Join Stack Overflow 74ls148 learn, share knowledge, and build your career. 74ls148 Tags Users Badges Unanswered. Besides tying the common lead of the switches to ground, I would also connect 4.
I connected the resistors as shown in the picture below, which 74ls148 give a HIGH state in 74ls148 output. Sign up using Facebook.
74148 , 8-to-3 Line Priority Encoder, SOIC, 74 LS, 74LS148
74ls148 I don’t know why you are connecting the enable lines 774ls148 the ‘ G1, G2A and B 74ls148 switches also. Sign up or log in Sign up 74ls148 Google.
In any case, in your example only inputs A, B and C should come from switches. So there is no way to drive any of the inputs low.
Post as a guest Name. Sign up using Email and Password. Second, make sure your switches are all off to begin with, and then turn only one on at a time 74ls148 you do turn on more than one, there 74ls148 a 74ls148 in the 74LS datasheet which will indicate what the output should be.
That said, when using a chip like 74ls148 LS you may want to 74ls418 the 74ls148 as shown below and use pullup resistors to 74ls148 the high levels on the inputs to the chip.