BS2e to power 12v @ 0.16A
nick412
Posts: 16
I am looking for the simplest (reasonably safe) way to power an electronic door strike (which the documentation says it is rated at 12v, 0.16A) from a Basic Stamp 2e, along with a 12v, 100mA buzzer controlled via a separate output pin.· Possibly via an opto coupler?
I read the Nuts and Volts article "Silicon Steroids for the Stamp Help Your Projects Heft Big Loads – Using Switching Transistors" http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv6.pdf and tried a 2N2222A (I could not find a 2N2222) transistor however could not seem to get it to work.· Not sure if I broke the transistor somehow, but from what I could see it was wired correctly, and I tried it twice with 2 new transistors.
I read the Nuts and Volts article "Silicon Steroids for the Stamp Help Your Projects Heft Big Loads – Using Switching Transistors" http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv6.pdf and tried a 2N2222A (I could not find a 2N2222) transistor however could not seem to get it to work.· Not sure if I broke the transistor somehow, but from what I could see it was wired correctly, and I tried it twice with 2 new transistors.
Comments
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- Stephen
The 2N2222A should be rated for 800mA. I wonder if this is more a problem with lack of protection for back EMF…I didn’t see any mention of a protection diode on the device.
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Chris Savage
Parallax Tech Support
When testing, I was using the buzzer which I was guessing did not need a protection diode (for the EMF?) like relays etc do?
The mosfet's appear to be even more complicated to use than transistors (at least the ones I found), therefore I think I will give it another go with the 2N2222A.
What do I need in terms of V, A, and W? (I am looking at what Maplin have available: http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=33843&doy=8m3#spec
From what I can see the case style I need is TO220.
Would the IRF540A work, datasheet: http://www.chipcatalog.com/Datasheet/849B84DF180C0CE4634E41A874D1AB66.htm
Post Edited (nick412) : 3/8/2007 8:55:29 AM GMT
I.e. I should connect it as in the diagram (without any resistors / diodes at all)?