I'm trying to design a stepper motor controlled using a potentiometer, operating at approximately 120 V with position controls using an Arduino. How do I go about designing this? Can I just use a rectifier and step down the voltage using a transformer/voltage divider?
The stepper motor isn't 120V, right?
You should probably buy a power supply, which converts 120VAC to an isolated, lower DC voltage. USB power supplies/chargers are popular and inexpensive but you may need more voltage, and possibly more current, for a stepper motor.
You can build a power supply from a transformer, diodes (or a bridge rectifier) and a capacitor. With a few more components you can make a regulated power supply (which holds a constant voltage if the input-voltage or load changes).
A transformer has no electrical connection between the primary and secondary (just an electromagnetic connection) so it provides the isolation. All power supplies have a transformer,
A voltage divider without a transformer is not safe because it's not isolated. If the AC wires get reversed (which can happen with an extension cord or a non-polarized plug, you can get 120V, or nearly 120V on the Arduino's ground even though the voltage across the Arduino is low. For example, it's illegal to sell a non-isolated product unless it's "double insulated" with no connections to the outside world. No USB connections or anything like that. And it's pretty hard to develop & debug a "hobby project" that's sealed inside a plastic box so you can't touch the circuitry..
And in general, voltage dividers are no good for power... They are only good for low-power signals,
What are the voltage and current needs of your project?
I would buy a power supply that is the highest DC voltage required by the project and use DC-DC converters (buck converters) to derive the lower voltages from that supply. For the Arduino use a DC-DC converter to 5V and apply the 5V to the 5V pin. Don't use the power plug or Vin.
What was your reason for choosing 120V?
Ah okay, thanks everyone, the answers really helped. On another note, is there a software/website that's like TinkerCAD circuits, for trying to design the circuit? User-friendly UI but with more components, as there's no options to add components like stepper motor driver and whatnot
The Wokwi simulator is popular with some mrmbers if a simulator is what you want.
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