analogRead

In the past blog post we used a potentiometer to provide a user variable voltage to one of the Analog In pin. We then used the value read from the Analog In pin to set the blinking delay of an LED. This resulted in the LED which was blinking faster and slower depending on how the potentiometer was set.

Potentiometer aren't the only circuit components whose provide a variable resistance. In fact there are many others: providing a different resistance its a common behavior in most sensors.

In the Arduino Base Workshop KIT I have two components of this type: a 4,7K Ohm Thermistor and a 10..40K Ohm LDR VT90N2. Let's have a look at them.

In this blog post I'll start experiencing with potentiometers and how to use them with Arduino.

Voltage divider circuits

There are situations in which one part of a circuit only needs a percentage of the available current. An example I already experienced is using an LED in series with a resistor. The resistor is used to limit the voltage which get to the LED which could otherwise get damaged. The same idea is used in voltage-dividing components, commonly called voltage dividers.

Voltage dividers find wide application in electric meter circuits, where specific combinations of series resistors are used to "divide" a voltage into precise proportions as part of a voltage measurement device. You can understand how voltage dividers works by having a look at the following picture: