Electronics → transistor uses more power?

noobie alert,

im trying to learn transistor currents now.

i have a relay that use 65ma to run its coil, when i run this through a transistor specifically a bc500, that current goes up to 91ma, i have a voltage drop from 4.85 to 4.61, seems like a significant increase for a small voltage drop, or does the transistor use power to run as well and thats what i am seeing?

It should use about a miliiamp more.

Depends on how it is wired and if you limited the base current.

Do you have a current limiting resistor of a suitable value connected to the base of the transistor?

Limiting the current going to the base is necessary, otherwise it will draw excessive current and damage the transistor.

Following your EEVblog thread. Is it working? Do you understand what they were trying to tell you?

Borrowed from EEVblog added voltages

Please have a look at the big bold diagrams in this page: »learn.sparkfun.com/tutor ··· nsistors

As other pointed out, you have higher base current, which can be reduced. You can measure that voltage drop too.

Yes. I am all set with this. I learned a ton. Sorry for not replying sooner here. I was fried afterwards. I also figured out my issue. Apparently there was a 100 ohm resistor in my 4.7k case this is what caused the .93ma off the emitter. So I'm thrilled to have figured it out

Always double-check component values before using!

Components do tend to jump from one bin into other adjacent bins from time to time.

Yeppers. Quality time so far. My eBay account has so much crap ordered its scary. Sure is fun.