It's a very small stepper at 18 ohm resistance per coil(2 of them) (4 phase).
I got: stepper in the picture, L9110, LM358, arduino.
I used an L9110 with the arduino. The stepper moved where it was supposed to move but with a lot of noise, vibrations during some frequencies. At higher frequencies it moved very smooth but at lower frequencies it became a clock. "tick", "tock", "tick", "tock".
I want to step with a sine wave signal. I want it to have an amplitude of 3V. How do I make such a circuit?
3 V / 18 ohm = 0.16 A
3 V * 0.16 A = ½ watt
My previous ideas that have failed:
- Use two pins (filtered pwm) on the arduino.
Fail: they can only give
20 mA safely. (18 ohm * 20 mA * 20 mA = 0.0072 watt). Too weak. - ^Use above idea with two LM358 as buffer for the two pins.
Fail: LM358 outputs about 1 mA (0V gnd, 5V vcc). - Use a linear analog voltage regulator.
Fail: It will be ineffecient and I don't have a linear analog voltage regulator. Though I could buy one. - Use L9110.
Fail: It only has a truth table. There's no analog voltages.
Since it's just a very small stepper that won't use more than ½ Watt I should be able to get away with a few components.
When it comes to software and digital things I'm a king. When it comes to analog circuits I'm a peasant. Please help this peasant you analog kings and queens.
Best Answer
Apparantly what I need is called a Push-Pull Amplifier.
This is the schematic that I made and decided to go for. In case anyone cares.