saving you costs: 4-digit LED display drive using 16f54

[tetsu-jp]

Nguyên văn bởi minhtienbk

the LEDs will be damaged pretty soon when we can't control the current passed them.

Thank you for your opinion I value it as well I value any kind of response.

However I second this opinion see photo: (attached).

It is true yes the "1" is a bit more bright than the others.
But this well could be compensated in software!

It is hard indeed to burn a LED using a button cell.
I use them to test LEDs before soldering.

When I write 1 to 3 years lifetime, it is based on own experience I had with gadgets. Maybe 50 of them. Sometimes wires or buttons break just after a few months. Even for expensive digital camera. The battery door broke after a few weeks.

One LED matrix circuit works for more than one year now. Same drive system, directly by the PIC ports, no resistors, 2.4 volts batteries. There is not any sign of LED damage.