+5 Proto Area & multiple circuits

[nebraska_e28]

I'm building the circuitry to configure the spare ports & have a few questions just to be on the safe side.

1. I've connected 2 of the spare output circuits to the left banded side of D9 to power them. Is it ok to add 2 more off this for a total of 4? Can the proto ground handle 4 of these? You can see in the picture that I bridged the positive side of the diode in the circuit to do this.

3. I inadvertently ran IAC1 & IAC2 to switch the 2 circuits I built. I know this isn't necessary, but will it cause any problems?

2. What is the purpose of the diode in this circuit? I posted the schematic I followed below.

Thanks!

[DonTZ125]

The relay coil is an inductive device; just like the ignition coil, it builds up a (much smaller, obviously) magnetic field that collapses when switched off, generating a voltage spike. The diode is a freewheel diode, allowing that flyback pulse to dissipate harmlessly through the relay coil, rather than through your electronics.

[nebraska_e28]

Ok, I understand on the diode now.


Do you know if it's ok to power multiple output circuits off D9 in the fashion I've done?

[Matt Cramer]

You aren't truly powering them from that point - you're providing a path to bleed off flyback spikes, and yes, you can use several connections there.

[nebraska_e28]

Sweet, thanks to both of you!