hi
i want to build a variable voltage to control a lamp
i was trying to use a mcp4151 digital 5k pot to control a tiny tungsten lamp 6v
and was wondering how can i get more current since the mcp is rated to micro amps
i want to control it digitally from an arduino hence the need for a digital variable voltage i guess from 3-6 volt
sorry if its a trivial question

 

i want to control it digitally from an arduino hence the need for a digital variable voltage i guess from 3-6 volt

While the Arduino has A/D (Analog to Digital) conversion it does not have D/A (Digital to Analog) conversion.

"A DAC is a circuit that allows you to translate numeric values into analog signals, so you can have output voltages variable from 0 to 5V by setting only a variable. If you want to do this with an Arduino different from the Due you can't without using an external chip".

I suggest you give this a read. If you want a voltage exceeding 5 Volts you will also need to consider that. This also considers an incandescent lamp as for lamps such as LED there are PWM (Pulse Width Modulation) solutions but as to an A/D conversion additional hardware is required,

Ron

 

Whats the wattage of the lamp ? You could use a mosfet as a switch. When the mosfet is conducting it supplies ground to your circuit.
50% pwm = 50% brightness etc.. You will probably need and external power supply depending on the power rating of the bulb.

 

First off He's not using adc he's using this.


Second he could use a npn and voltage divider , Then use the arduino to set the pot.
Or a mosfet and a throw away the mcp4151 and use PWM.

 

Welcome to AAC Refael!
If you are determined to use the mcp circuit you could control an external current or voltage source with it for driving the lamp, but using it does look like one of those journeys where the advice would be "If I were you I wouldn't start from here." The PWM approach that others have mentioned would be simpler.