Power supplies or schematics with just molex connectors?

**PrimusSucks** · 04-24-2004, 07:14 PM

I have a biscuit board, and its power connector is exactly like a hard drives power connector. So what I am looking for is a power supply, or schematic, that is just for this scenario. Actually, it would need two connectors... one for the biscuit board and one for the hard drive.

Source power will be the cig lighter...

Anyone familiar with such a product/schematic?

**Rob Withey** · 04-25-2004, 04:27 AM

If you don't need too much power, have a look at the ISR based power supply on my site. Kicks out 5v and 12v only (for a molex).

**PrimusSucks** · 04-25-2004, 12:32 PM

Is the MK2 what you are using now? If so, based on the specs of your system, that may be perfect. I am bringing back to life my MPXPLAY setup i used to run and my specs are going to be very close to yours.

Thanks for the info!

**PrimusSucks** · 06-05-2004, 08:31 PM

I can solder, but I can't read circuit diagrams well enough to know exactly what a 4v7, 4k7, and a 15k are. What i think:

4v7 Zener Diode (but what specs, i.e. voltage, current, etc)
4k7 Resistor? (but what specs, i.e. watts?)
15k: Resistor (but what specs, i.e. watts?) - Not sure I need this as I am not worried if my biscuit board is always running

Specifially, part numbers would be ideal so I can show the salesperson the specs of those part numbers. I went to a local surplus shop today and it was a waste of time because I didn't have more info on these three items.

Gracias,

**Pokey** · 06-05-2004, 09:02 PM

4v7=4.7volt zener, wattage size is really not that important, looks like they are using it for a clamp/reference.

4k7=4.7kohm, samo as above, reference

15k samo

i would use 1/4 watt on the above items, all the caps used should be at least 20-25% above the voltage they are tied to. (12v supply..l.15volt cap)

If you let the smoke out of the diode & resistor , increase to 1/2 watt

**Rob Withey** · 06-06-2004, 03:38 AM

Originally Posted by Pokey

4v7=4.7volt zener, wattage size is really not that important, looks like they are using it for a clamp/reference.

4k7=4.7kohm, samo as above, reference

15k samo

i would use 1/4 watt on the above items, all the caps used should be at least 20-25% above the voltage they are tied to. (12v supply..l.15volt cap)

If you let the smoke out of the diode & resistor , increase to 1/2 watt

Yup, just like Pokey says. Low power is fine for that, those components are a potential divider and clamp on the remote switch on wire. 4.7v zener (low power) and 1/4w resistors will be fine.

**PrimusSucks** · 06-06-2004, 06:40 PM

Pin 3 is like a power on/off switch correct? Is this really needed if you are not wiring direct to the battery (i.e. an already switched source)

**Rob Withey** · 06-07-2004, 04:04 AM

If you don't need the remote switch on/off, just leave pin 3 on both devices open, as specified in the datasheet from the TI website. In this case you don't need the 15k or 4k7 resistors, or the 4v7 zener. You should not tie the pin 3 from the regulators together.