I am building a 4 player game show circuit with 74LS04, 74LS20, and 74LS74 chips, which will turn on LEDs as well as trigger an optoTriac?.? to provide AC current for lights..
The original schematic had no values listed for the pull down resistors on the switches, so I just assumed a 1k would work based on another project I found in a blog.
I have breadboarded this five times, and even wire wrapped it, but it will not work.
I have downloaded the IC data sheets, but don't really understand what they mean.
I am a pastor, not an electronics guy, but am willing to learn. I understand BASIC concepts, but am still working on the Ohms law and so forth.
My two questions are A) if you have your base input current from your transformer, and know you need a resistor, where on the data sheet do you get the required info to calculate the size of the resistor? V=IR, so voltage is 5 from transformer, R will be the resistor, so I need the # from the data sheet to say what is the "I" value to calculate R... but don't get where it is listed. Does each pin of an input on a chip need a resistor because of different requirements?
Question B) related to A, in that I can not get my circuit to work, and wondered if I just am not giving it enough amps. I am using an old phone charger - 5v 20mOhms. ICs are 5v, but how do I figure how many amps the circuit needs? 5 ICs, plus power for triacs, and LEDs. Is it cumulative (a sum of all required power for each chip, led, and triac combined) or just supply based on chip with highest requirement? Where on the data sheet find this?
Any help here so I can understand this IC stuff would be greatly appreciated.
Please feel free to e-mail me directly - <snip> (Eastern time, USA)
The original schematic had no values listed for the pull down resistors on the switches, so I just assumed a 1k would work based on another project I found in a blog.
I have breadboarded this five times, and even wire wrapped it, but it will not work.
I have downloaded the IC data sheets, but don't really understand what they mean.
I am a pastor, not an electronics guy, but am willing to learn. I understand BASIC concepts, but am still working on the Ohms law and so forth.
My two questions are A) if you have your base input current from your transformer, and know you need a resistor, where on the data sheet do you get the required info to calculate the size of the resistor? V=IR, so voltage is 5 from transformer, R will be the resistor, so I need the # from the data sheet to say what is the "I" value to calculate R... but don't get where it is listed. Does each pin of an input on a chip need a resistor because of different requirements?
Question B) related to A, in that I can not get my circuit to work, and wondered if I just am not giving it enough amps. I am using an old phone charger - 5v 20mOhms. ICs are 5v, but how do I figure how many amps the circuit needs? 5 ICs, plus power for triacs, and LEDs. Is it cumulative (a sum of all required power for each chip, led, and triac combined) or just supply based on chip with highest requirement? Where on the data sheet find this?
Any help here so I can understand this IC stuff would be greatly appreciated.
Please feel free to e-mail me directly - <snip> (Eastern time, USA)
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