Powering a 12v and 5v servo with an Arduino Uno

I have a 12v linear servo, 5v rotating servo and a 5v LED bar graph to display position of the linear servo. Can I power them all via a 12v source using the 12v Arduino input jack and the 5v pin on the Arduino?

No. The Arduino 5V pin cannot be used for motors or servos. Use a stepdown converter instead (minimum current capability 1 Ampere per SG-90, 2.5 Amperes per MG996R):

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Yes, noticing the reply from @ jremington
but don't power any motor via the barrel plug and tap 12 volt from Vin!

Gil's Crispy Critter Rules for Processor Hardware:

  1. Rule #1: An Arduino is NOT a Power Supply!
  2. Rule #2: Never connect anything inductive (motors, speakers) directly to an Arduino!
  3. Rule #3: Avoid connecting or disconnecting wires while the power is on.
  4. Rule #4: Do not apply power to any pin unless you are certain of what you're doing.
  5. Rule #5: Do not exceed the maximum voltage ratings.
  6. Rule #6: Many Arduinos cannot power transmitters directly.
  7. Rule #7: Before powering your project, take a break and double-check the wiring.

LaryD’s Corollaries:

  1. Coro #1: When starting out, add a 220Ω resistor in series with both input and output pins to protect against shorts.
  2. Coro #2: Invest in a Digital Multi-Meter (DMM) to measure voltages, currents, and resistance.

Note: Violating these rules can turn your Arduinos into crispy critters. For optimal performance, keep your wires under 25 cm (10 inches).

Additional Tips:

  • The L293 motor driver, though common, is inefficient as it can lose around 3V as heat when driving both legs of a motor. Consider using a motor driver with MOSFET outputs to reduce heat loss and conserve battery power.
  • For more on powering Arduino boards, explore this guide: Powering Alternatives for Arduino Boards.

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