[Newb Question: 12v-80ma transistor switch]

Yeah, after breadboarding it. IT WORKS.  :D

woot!

Thanks All

[Newb Question: 12v-80ma transistor switch]

After figuring out I fried one of the decoders or trans/ receiver units I bought all new parts. Now, I have a 4 volt output!  :D

[Newb Question: 12v-80ma transistor switch]

Thanks.

feel free to move the topic, I was unsure if this was the proper thread to post in anyway.

[Newb Question: 12v-80ma transistor switch]

Forgot to ask, how do I match current gain w/ a transistor. There are a series of numbers w/ different ratings for current and voltage. The chart only goes to two volts. When i find the right current gain, how do I match it? Won't a resistor drop the base voltage below the triggering tvoltage for a transistor. I only have .5-.7 going out from the receiver circuit which triggers it.

Thanks

[Newb Question: 12v-80ma transistor switch]

A 12V relay needs about 10V to turn on because...

Thanks, that makes sense.


Can't the pnp be substituted w/ an npn in the circuit instead. I need it to be off at: 0 and on at : 1

[Newb Question: 12v-80ma transistor switch]

Just to be on the safe side, what NPN would you recommend. Everyone I have chosen in the past doesn't work properly. Oh, and the base input to the transistor is .7 volts. If you are refering to the supply voltage, why would 5v keep it latched on? Just curious.

[Newb Question: 12v-80ma transistor switch]

Yes, the circuit w/ the 5 volt power supply is the one I'm refering too. Audioguru, the circuit you've posted is exactly what I need, only NPN. I assume I can substitute an NPN w/ the same ratings for it. I have gone through several transistors, as long as the 2n4403 can handle the 80ma and 12v, I will be set. Thnaks!

*To clue anyone in who is interested, this is for automating the openning of a locker. 
*Mechanics, now that's something I can deal with. ;D

[Newb Question: 12v-80ma transistor switch]

Ok, I know this is a newb question, but i have tried everything. So, I have a 12 volt, 80 milliamp relay coil connected to the emmiter of a transistor (TIP3055), the base input voltage of .7 volts, and the collector leading to ground. To protect the transistor, I have a diode (Rectifier: diode [2.5 amps 1,000v]) between the resistor coil. Previously, with a different transistor (one I scrapped from an RC Car) it just locked in the on state, where as with the current one mentioned above, it doesn't switch at all. ??? Someone please enlighten me! I altered the schematic, replacing the 5 volt relay with a 12 volt from "http://www.rentron.com/Files/TWSAKIT.pdf"

Thanks.