Relay triggering voltage

Thread Starter

J253

Joined Dec 2, 2023
5
Hello all , I have made an optocoupler relay PCB.. that I'm using with my stm32 development board.. that relay power at 5V and triggered at 3.3V .. sometimes my controller board give less voltage like 3.2 or 3.21 at that time it's not triggering can someone tell me what's going on or help me ..
 

AnalogKid

Joined Aug 1, 2013
11,022
When you post your schematic, make sure that each component has a unique reference designator (R1, R2, etc.) and the component's value. Without this information, discussing how the circuit functions is very difficult.

ak
 

dl324

Joined Mar 30, 2015
16,897
can someone tell me what's going on or help me
Not without more information. What is the part number for the relay and where's the schematic?

Your posts would be easier to read (meaning you're more likely to get responses) if you used proper grammar (capitalization, paragraphs, and sentence terminators).
 

LowQCab

Joined Nov 6, 2012
4,052
Most Relay manufacturers will provide "Must-Break" and "Must-Make" Voltages,
unless, of course, You got your Relay from China.
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.
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dl324

Joined Mar 30, 2015
16,897
Of the relays I've used, pick-up voltages of 70-80% of the nominal coil voltage were specified. 70% required selected devices.

You're below 65%.
 
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