Inductors with DC current ratings up to 30 A use compact ferrite core made from high-saturation, low-loss material; employs flat wire for high-frequency operation; and uses transistors as on/off switches. Converted to series of pulses via PWM, signal is amplified and converted into analog signal as it goes through low-pass filter. Enclosed shape of core provides added shielding, and inductance values are available from 10, 22, and 33 µH and can be adjusted to any value up to 100 µH.