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Topic: Relay Controlled with ESP-8266  (Read 1 time) previous topic - next topic


This is the one I am using. It is capable of providing 800mA.
Possibly, if you are dropping from only 5 V.

If the Optocoupler is not required I will remove it from the schematic.
If you have the same ground connected to both its input and output, is is not isolating anything at all.  :smiley-eek:


You do not need U3, it is superfluous. R3 is too high, it should be 220 ohms for the relay used. The 2N3904 is not appropriate, too close to its max ratings. To select a far better switching transistor, do you have preference for surface mount or thru-hole devices?
Is the 2N5401 good for the job?


Jan 15, 2019, 01:16 am Last Edit: Jan 15, 2019, 01:17 am by WattsThat
Wrong polarity, it is PNP. The 2N2222 (or PN2222) is a common NPN that would handle the 200ma relay you've specified.

In general, you want a device characterized as a switching transistor rather than an amplifier.
Vacuum tube guy in a solid state world

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