Resistor Help Needed

[mezerak]

Im trying to work out what resistor should I use for a school project but I keep getting confused I need to drop a 6V input to a max of 5.25V output but a min 4.25V, can anyone help me out with this?
Kind regards

-Vincent

 

[I²R]

Apply your Ohm's Law.

 

[Pommie]

Two diodes in series will drop it to 4.6V

What are you powering?

Mike.

 

[Holger]

hello

Im trying to work out what resistor should I use for a school project but I keep getting confused I need to drop a 6V input to a max of 5.25V output but a min 4.25V, can anyone help me out with this?
Kind regards

-Vincent

you must now how much current that is flowing i.e 6volts minus 1 volts and say .1 A is abt 10 ohms..but maybe you need some low voltage regulator or a simple "voltage divider"..excuse my english ..i'm from sweden...Holger

 

[mezerak]

Two diodes in series will drop it to 4.6V

What are you powering?

Mike.

Im trying to power a USB device, but the thing i need to produce the current is 6V and a usb doesnt go any higher than 5.25V

 

[Pommie]

If you don't know what current the device will draw then a resistor is no use. The simplest method is to connect two diodes in series with the positive supply - 1N4001 will handle 1A and USB can only supply up to 500mA.

Mike.

 

[Hero999]

Where are you getting the power supply from?

Use a low droput regulator.

Be warned, if it's four AA cells, the voltage will quickly drop to below 5V which where even most low droput regulators stop working.

 

[tonio]

hello,

Voltage dividers are good as long as the current drawn by the load is low (10 x less ) compared to the current flowing in the resistors network.
now if you do not have a fixed load or if the load takes up too much current your best bet is either a low drop out voltage or diodes in series....

best of luck
Antonio