We will be closed on November 25, 2021 and November 26, 2021 in observance of the Thanksgiving holiday. We will resume normal operations on November 29, 2021. Wishing you a safe and happy holiday from all your friends at SparkFun!
Receive a free SparkFun USB Thumb Drive with every order this weekend. Details.
Track My Order
Frequently Asked Questions
International Shipping Info
Mon-Fri, 9am to 12pm and
1pm to 5pm U.S. Mountain Time:
February 2, 2009
Tutorial - Controllable Power Outlet
about 13 years ago
However, thinking at the CE of the transistor too, the voltage at the resistor will be U<3V, so R will be <150 Ohm, not 1k!
Oh, sorry the resistor is not grounded as i see...
Supposing the LED needs 2V, it remains for the series resistor 3V, we know that the LED needs 20mA (0.02A); using Ohm's law results R=U/I=3/0.02=150 Ohm for the series resistor. I don't understand how did you get 1K for it?! Maybe a mistake?
No public wish lists :(