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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? |
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shdesignsPowered By Infinite Improbabilty Drive Premium Member join:2000-12-01 Stone Mountain, GA
1 recommendation |
It should use about a miliiamp more.
Depends on how it is wired and if you limited the base current. |
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TheMG Premium Member join:2007-09-04 Canada |
to LittleBill
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. |
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SparkChaser Premium Member join:2000-06-06 Downingtown, PA |
to LittleBill
Following your EEVblog thread. Is it working? Do you understand what they were trying to tell you? Borrowed from EEVblog added voltages
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lutful... of ideas Premium Member join:2005-06-16 Ottawa, ON |
to LittleBill
said by LittleBill:im trying to learn transistor currents now. Please have a look at the big bold diagrams in this page: » learn.sparkfun.com/tutor ··· nsistorsAs other pointed out, you have higher base current, which can be reduced. You can measure that voltage drop too. |
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to SparkChaser
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 |
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TheMG Premium Member join:2007-09-04 Canada MikroTik RB450G Cisco DPC3008 Cisco SPA112
1 recommendation |
TheMG
Premium Member
2015-Apr-19 3:23 pm
said by LittlebillS :Apparently there was a 100 ohm resistor in my 4.7k case this is what caused the .93ma off the emitter. Always double-check component values before using! Components do tend to jump from one bin into other adjacent bins from time to time. |
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Yeppers. Quality time so far. My eBay account has so much crap ordered its scary. Sure is fun. |
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