Choosing the Right Component

[lightnb]

I found a schematic online for a project that I would like to do, but some of the component descriptions are vague- that is, when I go to an electronics catalog, there's still about 100 choices that meet the requirements.

For example, C1 calls for a 10nF Capacitor. It doesn't specify type, voltage, tolerance, dimensions or anything else. So I'm a bit confused as to which capacitor I really need.

I'm hoping that someone with electronics experience could look at the schematic, and based on context, point me in the right direction.

The schematic is attached- I'm building the isolated version.

What it Does:

When completed, this device should connect to a computer via the USB port. It is controlled by software on the computer, and generates a DMX (DMX512 protocol) signal.

Thank you for your help.

 

[things]

is that for controlling a dmx capable lighting or something like that. as for the capacitors, i don't think it matters what type it is, but as long as the capacitor is rated higher than the voltage input you should be right, or if the circuit is polarised its a different story.

 

[lightnb]

Thanks- yeah it's for lighting control.

The input is 9v, so any capacitor with a voltage greater than 9v should work? And it won't affect performance in any way?

What about 'ferrite bead'? Will any ferrite bead do?

How do I know if the circuit is polarized?

 

[Hero999]

Well I've never seen a polarised 10nF capcitor before so I wouldn't worry.

 

[philba]

For ferrite beads - I'd add up the current each IC will draw and then pick a bead that is rated well (2X) above that. Mouser has a decent selection.

That circuit has no bypass caps for the ICs. I'd add them - 100nF across the Vcc and Gnd leads of each chip.