[SOLVED] 4067 Demux working as Mux

[djeceymca]

Hello Guys,

I want 4067 IC as Demultiplexer so that I can connect different relays to control my ultimate load.

Now the problem is 4067 is somehow creating it as Multiplexer configuration as GND is connected to relay and which is ultimately connected to O0.

Could you please suggest How can I trigger relay with Demultiplexer?



Regards,
Dev

 

[d123]

Hi,

I'm not sure the 4067 can provide sufficient output current to energise a relay coil, the CD4067 datasheet says max. 100mW per output transistor; even so, if it isn't a quick sketch to give the idea, in that picture the relay coil is missing a flyback diode, and there should be a BJT or MOSFET between IC pin and relay coil, simplest with an NPN where that coil ground connection is, and the "top" of the coil connected to supply V+.

 

[KlausST]

Hi

I agree with d123.

* Fuctionally you may use the 4067.
* There are dedicated relay driver ICs. They may be controlled with SPI or I2C
* you may use some logic IC like HC138 combined with a LED driver like ULNxxxx

There are many, many example circuits here in this forum and even more in the internet.

Klaus

 

[FvM]

You should mention relays coil resistance.

 

[djeceymca]

Thanks, I also thought the same approach if relay is not getting triggered directly via microcontroller output.