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Amplifying ATmega8 signals

I am doing my final project for school at the moment.

I have a bit of a problem.

I use my ATmega8 with a BD243C transistor to switch a relay.

Now is the problem that the signal that goes to the transistor is to small to fully switch the relay. I was wondering if I could use this(http://www.datasheetcatalog.com/datasheets_pdf/T/L/0/7/TL074CN.shtml) TL074CN IC for amplifying the ATmega8 signal and so fully switch the relay. Can this be done?

 

I have not much time left to finish this project, so I would appreciat all help.

 

Danny Temmerman

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or...

you can use one more transistor, mounted as amplifier between your micro and your original transistor

 

something like

http://2.bp.blogspot.com/_DNAGtVGJgew/SZs41rrC-vI/AAAAAAAAAEQ/tAvYZOBJd0g/s400/solenoid_diagram.png

but I think one transistor should work.

there are some nice simulators out there that you can use to help you do all the calculations

 

Tnx for the advice, but I already bought that chip in a hurry.

You think the chip will work? Hope it does.

But I gues it was better to buy a few small transistors.

But hey, I will first try with chip this thuesday. And if that doesn't work I will go with the transistors.

 

 

Tnx again, Danny Temmerman

The relay operates at 5v? or do you have external power just for the relay(s)?

No, its a 12V  relay.

My ATmega8 is run at 5V with a voltage regulator and the relays are switched at 12V throught the transistors. The relays switches motors of around 10A.