View Single Post
  #31   Spotlight this post!  
Unread 09-07-2012, 15:44
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,133
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Turning LEDs on/off


While we're on the subject of series resistors for the signal line, attached is a sketch of the circuit using one of those NPN transistors you got in the package you bought (2N3904).

Can someone please check my calculation for the base resistor?

I tried to size it to saturate the transistor with a 5V signal.


Attached Thumbnails
Click image for larger version

Name:	LED_NPN2.jpg
Views:	19
Size:	144.3 KB
ID:	12874