From 12V DC to 5+ V DC How to?

I should also point out that the power supply for the device shows the following: OUTPUT: +5V 1.5A Output Power: 8W MAX

Use diodes in series. Each will drop the voltage by about 0.6 volts.

You have to use a voltage regulator, because the input voltage will increase while the bike is running. A simple series resistor or a group of series diodes won't work. Here's a circuit:

You will need a good heatsink on the LM350, something rated 7 degrees C per watt or better. Digikey HS276-ND is rated 2.5 degrees C per watt and costs $1.44 - it will keep the LM350 under 60 degrees C, which is great. The 2.5 ohm resistor needs to be 10 watts. The 270 and

For a smaller and non-heat producing solution, you could use 445-2435-ND from Digikey. It is a DC-DC converter module that accepts 9 to 18 volts in, and produces

Ed

Will this work?

Probably no

That is a good "cheap and dirty" way to reduce the power. They don't cut down the voltage they just switch it on and off rapidly - the average power is less and efficiency is high - but it won't work for devices that are sensitive to voltage or anything with a large filter capacitor - the cap will charge to the peaks and you'd have 12V going into the 5V electronics.

It can be made useful - with an inductor, pulse width modulator circuit, and a degree in electronics - and cheaper to design from scratch.

That particular gizmo is a controller for a brushless motor. It is designed to supply both a variable voltage and variable frequency to a small three phase motor to allow it to run from batteries - very efficient way to control a motor speed - but not what you say you want.

If you have a 5 volt motor and want to run it on 12 V just build a simple single phase pulse width modulator to lower the average power to the motor (a brush type motor doesn't care that it's getting 12 volt pulses for 40% "ON TIME" versus the 5 volts it is rated at)

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Are you sure you need 1.5 amps? A lot of simple there terminal regulators will fit the bill - and a lot of them only put out 1 amp. You can get up to 5 amp three terminal regulators but cost and complexity increases.

Lot of places on a bike would make a good heatsink - the old Triumphs used to mount a big 50 watt zener diode to the air intakes for the carbs - that was the "regulator" for the electrical system.

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Your can use this program to design a power supply with a voltage regulator:

It might be a good idea to add some overvoltage protection before the regulator. A power resistor in series with the supply and a 20 volt transient suppressor diode to ground will probably be enough.

okay what about this thing will this work? The only thing I am worried about is that I am going from 12 to 5 which is a 7V drop. I am told that will generate lots of heat. But I would think this device would take care of that

That's a *nice* looking device. Don't know if one will work for you, tho - you might need 2. Your original power supply is capable of 1.5 amps - maximum for the device at the url is 1 amp. If your current requirement is < 1 amp, one should work fine. The url says they can be put in parallel, so if you use 2 in parallel you can exceed 1.5 amps.

Heat is not a problem with switching regulators like it is with linear regulators, and DE-SWADJ is a switcher. Sounds like you would be in good shape with one (or perhaps 2) of them.

Ed