Hi all,
Not a "great" project, but something I liked doing.
It's always bothered me to have to line up the appropriate leads on an LED to the appropriate leads on an LED tester - I sometimes forget - "long is what?"
So as an exercise I thought about making an apolar LED tester such that the leads can be inserted either way and the LED will flash if it is good. To learn more about transistors (doing my "transistor phase" now), I started drawing diagrams and building examples, and after a few iterations got this:
Hooray! It works.
I learned about choosing a transistor based on CE voltage/current needs, and learned about calculating the value of the base resistor.
You hook up two leads from a microcontroller, one to each of the connected bases, and then alternately pulse the leads 1,0,1,0 etc. Connect an LED between the two poles and "on" "off" "on" "off" no matter what the polarity.
The next issue is a "simple" transistor circuit to alternately turn the bases on and off. The smallest "flasher" unit I could find is the classic two transistor flasher like THIS one.
Do you think that I could take a wire from each of the LEDs and connect it to the two bases of the LED tester to alternatively turn the bases on and off? (ground goes to ground across the two circuits)
Any other ideas?
Thanks in advance.
Not a "great" project, but something I liked doing.
It's always bothered me to have to line up the appropriate leads on an LED to the appropriate leads on an LED tester - I sometimes forget - "long is what?"
So as an exercise I thought about making an apolar LED tester such that the leads can be inserted either way and the LED will flash if it is good. To learn more about transistors (doing my "transistor phase" now), I started drawing diagrams and building examples, and after a few iterations got this:
Hooray! It works.
I learned about choosing a transistor based on CE voltage/current needs, and learned about calculating the value of the base resistor.
You hook up two leads from a microcontroller, one to each of the connected bases, and then alternately pulse the leads 1,0,1,0 etc. Connect an LED between the two poles and "on" "off" "on" "off" no matter what the polarity.
The next issue is a "simple" transistor circuit to alternately turn the bases on and off. The smallest "flasher" unit I could find is the classic two transistor flasher like THIS one.
Do you think that I could take a wire from each of the LEDs and connect it to the two bases of the LED tester to alternatively turn the bases on and off? (ground goes to ground across the two circuits)
Any other ideas?
Thanks in advance.
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