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16f876A directly interfacing repay?

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neazoi

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Hello, I need a little bit of help here
I would like to use the 16f876A or similar 28-pin micro to switch on/of some relays.
If the relays have a 5V coil, can I switch them on by directly connecting the microcontroller pin to the coil, or do I need a transistor switch?

I prefer driving the relay directly but I do not know how much current can the micro provide on each pin.

The relays coils datasheet is this one http://www.techno-star.biz/relays/ea2.pdf


Also what about latch type relays, which require current only when switching? Would I be able to directly drive their coils using the micro?
 

hussain_kiet

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it is recommended that you need a transistor to switch the relay other wise it may damage your controller...
 
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    neazoi

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neazoi

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Even if I use latch type relays?
What is the max output current of the 16f876A btw?
 

horace1

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I agree with hussain_kiet to use a transistor such as a BSP130 D-MOS logic level FET to drive the relay. Also if the relay is switching high currents or voltages an opto isolator before the replay is a good idea.
 

abidr

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It depends on the type and number of relays.
If number of relays is more than 1, I would personally prefer using a ULN2003.
 

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