# Arduino with zener diode

Well I want to decrease the output voltage outputted from the digital outputs of arduino. I don't want it to be done with a specific way, but I have read that it can be done with using zener diodes. Because I am not so experienced to be able to use them and understand them good enough to apply them can anyone explain me how to use them?

While you're there, also look up "Voltage Divider".

If you can explain what it is you want to feed the signal into, why that signal voltage must be lowered and what you want it lowered to, you might get some additional suggestions.

I don't want it to be done with a specific way,

You want it done some random way?

I meant not only by using zener diodes... if u know any other way that works as well... I can hear it as well.

edit: Ohh and the voltage must be lowered because I want to connect.. lets say a sensor with a board but the sensor makes use of lower voltage than the board output.

If it is a plain digital signal going to a relatively high impedance destination, then you will want to use a voltage divider.

lets say a sensor

Oh, go on...you can say it.

Seriously, until you get you basic electronics sorted out, you're going to burn through a ton of "sensors"

I have basic circuit knowledge like... I can calculate the voltage the resistors the current of a circuit with some given information, I know Kirchoff laws and ohms, lens. I know about electrical oscillations. But I am not so advanced to know how to use diodes or how to reduce voltage especially when the equation is V=I*R

Also I have read that diodes are a safer way to reduce voltage. Is this true? Can anyone draw a sample of how do diodes work?

Here's a simple circuit using a zener (click on the image to see it)

The PWM output is a 5 volt signal of varying duty cycle (mark to space ratio). The zener diode subtracts its voltage rating from the 5 volt output to produce a reduced output. For example, if the zener is rated at 2.1volts the output will be 2.9 volts.

jack

Jack:

How are you dealing with the current (or power) rating of the Zener in your circuit?

Don

On the basis that the arduino can output only 40ma without going into self destruct the maximum zener required power rating is
5 x 0.04 = 200mW. That's based on using a 5 volt zener feeding into a dead short with 100% duty cycle of the PWM. To protect the arduino one should fit a resistor in the output of the zener to limit current to 40ma. The maximum resistor required is 5 / 0.04 = 120ohm. Again this is based on 100% duty cycle feeding a dead short but this time with the zener voltage set to zero volts
jack

Also I have read that diodes are a safer way to reduce voltage. Is this true? Can anyone draw a sample of how do diodes work?

They don't reduce voltage, but limit voltage above a specified value by shunting current when voltage is at the specified value. If the current available is above the zener rating, the zener may burn up. Also, zeners apparently require a certain minimum current moving thru them to shunt at the specified voltage value. You need to check out the voltage divider suggestion, with a zener in the circuit for added protection.