ORing 555 outputs?

@lem0nhead-ekdAZa • Oct 19, 2024

Oct 19, 2024

1.2K

hello
I want to OR three 555 outputs
for example, I have a LED that should be on when ANY of the 555 outputs (pin 3) is on

do I need to use a logic OR or would it be ok to just connect the 3 outputs together?
maybe with a diode to protect the pin 3?

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sauravgoswami

@sauravgoswami-UAfTlI • Jun 1, 2009

If you are using a single LED then you can use an OR gate or a multiplexer,and if you are using individual leds then there is no need of that as you simply connect the LEDS to the IC 555,through a resistor and a diode if needed
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Lem0nHead

@lem0nhead-ekdAZa • Jun 1, 2009

sauravgoswami
If you are using a single LED then you can use an OR gate or a multiplexer,and if you are using individual leds then there is no need of that as you simply connect the LEDS to the IC 555,through a resistor and a diode if needed
it's a single LED
I tried connecting the 3 outputs together with a diode (to protect pin 3) and it worked
is it a nasty solution that may overheat, or something like that?
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sauravgoswami

@sauravgoswami-UAfTlI • Jun 1, 2009

well then use a three input OR gate it will be simple and better option,make sure to supply to LED through a resistor!!
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Ashraf HZ

@Ash • Jun 1, 2009

Yeah, a cheap CMOS 4071 chip will do. Just chain two of the gates together 😀
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swapnakumar

@swapnakumar-lJkNkk • Jun 1, 2009

yes u can OR the outputs and then connect the output to a led to indicate on/off condition
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