Passing signals with no current.

[eem2am]

Hello,

I have a microcontroller which is connected via a connector to signals from another PCB.

The header used is the following one......
http://www.molex.com/molex/products/datasheet.jsp?part=active/0022112062_PCB_HEADERS.xml

......the microcontroller input , as you know, draws no current, as its an input...so therefore no current is passing through this header (connector).

I believe that there are minimum current levels for metal to metal connectors?

Since my connection passes no current, will it be OK?....(the connection surface is made of gold)

 

[(*steve*)]

Some current will always pass, although it may be very small.

At such low currents contact resistance is generally not an issue.

You should be fine.

 

[davenn]

Hello,

I have a microcontroller which is connected via a connector to signals from another PCB.

The header used is the following one......
http://www.molex.com/molex/products/datasheet.jsp?part=active/0022112062_PCB_HEADERS.xml

......the microcontroller input , as you know, draws no current, as its an input...so therefore no current is passing through this header (connector).

I believe that there are minimum current levels for metal to metal connectors?

Since my connection passes no current, will it be OK?....(the connection surface is made of gold)

If you have a signal you have a current flow, you cannot have one without the other

Dave

 

[KrisBlueNZ]

As Dave and Steve have already pointed out, there will be SOME current flow, even if it's just a few microamps.

AFAIK, low-current gold-plated connectors, switches, and relay contacts don't have minimum wetting current requirements, because gold doesn't oxidise. AFAIK.

These requirements are more applicable to medium-power and high-power relays and switches, due to the possibility of oxidation of the contacts.

http://en.wikipedia.org/wiki/Wetting_current

It's good practice to put a pull-up or pull-down resistor on any logic input that is being fed from off-board so that if the interconnection fails, the signal will assume a consistent and safe level. This resistor will also cause some current flow while the signal is in the opposite state.

 

[Harald Kapp]

The contacts are gold plated, whic is always a good sign for low currents, since no oxide barrier can reduce the current flow.
The data sheet says Application: Signal, Wire-to-Board

So it should be fine.