Working progressively: Part V (Breadboard redux)
Posted Mon, Apr 18, 2005 at 12:40 AM
The new breadboard layout is so much more compact than the old one! Note that instead of column scanning, I am now row scanning.
(Big thanks to Nick over at InterAccess for recommending the chips to me... and he didn't even mean to.)
It uses a TD62783 transistor array for the source and a ULN2803 transistor array for the sink. Plus the usual 220 ohm resistors.
Both of them work almost the same way:
- Pin1 is input from the Stamp and amplifies the signal straight across to the other side (Pin18)
- Pin2 amplifies across to Pin17
- and so on until Pin8 --> Pin11
On the TD62783, Pin9 goes to the power suppy and Pin10 to ground.
On the ULN2803, Pin9 goes to ground and Pin10 is left unconnected. (To be honest, why Pin10 is unused is a mystery to me. But it works! And nothing goes up in smoke!)