On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter"
wrote:


Once you have a 555 clock running you can hook up an old CD4013B like drawn
below. This type of components runs on power supplies from 3 to 20V. Of
course you have at least one problem left as these type of components can
sink only a few mA of current. So your LEDs will be pretty dim or you have
to use high efficiency LEDs. The series resistors can also be much lower
then calculated as the outputs have an internal resistor inside. The best
thing you can do is using an extra IC, a CD4050B. This one contains six
buffers which are able to sink enough current to drive a LED.


Vcc 3-20V +-----+-----+-----+-----
| | | |
.-. .-. .-. .-.
| | | | | | | |
| | | | | | | |
'-' '-' '-' '-'
| | | |
| | | |
V V V V
- - - -
| | | |
| | | |
| +--------+ |
| | | |
| | +--------------+
.----. | | .---- | |
+-----|D0 Q|---+--|-----|D1 Q|---+ |
| | _| | | _| |
| +--| Q|o-----+ +--| Q|o-----+
| | '----' | '----' |
| | CD4013B(a) | CD4013B(b) |
Clock | | | |
----------+-----------------+ |
| |
+-----------------------------------+

---
Ah, yes... the quadrature encoder! Good one! It didn't even cross
my mind. I must be slipping...


--
John Fields
Professional Circuit Designer