Can I use 5V power with MR16?

[fjaust]

Hi,

I have some strobes that require a 5v power source and I was thinking of using the MR16 to control them. Can the MR16 operate OK with a 5V power supply?

Thanks, Scott

[dmaccole]

No, the 7805 on the board is going to require at least 7 volts to operate correctly (8 or 9 would even be better). But you could run the board with 12 volts and then step down by putting a resistor inline between the board output and your 5v strobes.

Could you provide a link for the strobes? I'm still debating my strobe strategy.

HTH.

\dmc

[kylec]

You can control 5 volt devices, but you have to supply 12v to control the board, and use a different supply for the 5v.  You are not allowed to view links. Register or Login

[rm357]

Dmaccole is correct. The 7805 voltage regulator will not function at 5 volts.

The suggestion to run 12volts at 40% is also bad. The MR16 uses pulse width modulaion to control brightness. At 40%, you would be getting the full 12 volts 40% of the time and 0 volts the remaining 60% of the time.

There are two ways to make this work. We will dismiss modifying the board and assume you have both 5 & 12 volts available. Connect the 12 volts to the proper terminals onthe board. Connect the ground wire from the 5 volt supply to the ground terminal on the board. Connect +5v to your strobe or other device and connect the ground lead from the strobe to the approriate channel GND terminal on the mr16.  The mr16 swiches the ground lead, not the source lead. Do not connect anything to the pos terminal - that is connected directlt to thepositive input terminal.

[fjaust]

Thanks for the suggestions everyone.

Could you provide a link for the strobes? I'm still debating my strobe strategy.

\dmc

dmc, the strobes I have are the TPR1 LED strobes from ACL. I got 100 of them in a group buy they did late last year but have only just got around to getting them all together (doing SMD soldering with an iron is so slow when you aren't experienced with soldering anything !!).

Thanks, Scott

[RJ]

Dmaccole is correct. The 7805 voltage regulator will not function at 5 volts.

The suggestion to run 12volts at 40% is also bad. The MR16 uses pulse width modulaion to control brightness. At 40%, you would be getting the full 12 volts 40% of the time and 0 volts the remaining 60% of the time.

There are two ways to make this work. We will dismiss modifying the board and assume you have both 5 & 12 volts available. Connect the 12 volts to the proper terminals onthe board. Connect the ground wire from the 5 volt supply to the ground terminal on the board. Connect +5v to your strobe or other device and connect the ground lead from the strobe to the approriate channel GND terminal on the mr16.  The mr16 swiches the ground lead, not the source lead. Do not connect anything to the pos terminal - that is connected directlt to thepositive input terminal.

This is correct, we switch the Ground (-) so you can run the board from 12v and run the lights from 5v as said.

Or you can remove the 7805 and jumper across it if you 5v DC is regulated to 5v and not like a 5v wall wart.

RJ

[dmaccole]

dmc, the strobes I have are the TPR1 LED strobes from ACL.

Thought they might be something new ... well, I guess they're new to you ...

\dmc

[fjaust]

Or you can remove the 7805 and jumper across it if you 5v DC is regulated to 5v and not like a 5v wall wart.

RJ

my 5V power supply is regulated.
are these the two pins that need to be jumpered (see attached pic)?

[n1ist]

For the 7805, you want to jumper the two outer pins.  The center one is ground; make sure your jumper can't short to it.
/mike

[fjaust]

For the 7805, you want to jumper the two outer pins.  The center one is ground; make sure your jumper can't short to it.
/mike

thanks n1ist !!