Electrical4U 
An electrical motor becomes a servo motor only when a servomechanism closes the loop around it. A DC motor used that way is a DC servo motor. Among types of DC motor you will see a shunt wound DC motor, a series DC motor, a separately excited machine, a permanent magnet DC motor and a … Read more
What is a Nyquist Plot? A Nyquist plot is a polar or Cartesian graph used in control engineering and signal processing to judge closed-loop stability from an open-loop transfer function G(jω). In Cartesian form the real part of G(jω) is X and the imaginary part is Y. Frequency ω is the parameter along the curve. … Read more
A transfer function is the Laplace ratio of a linear control system output to its input, taken with all initial conditions at zero. A block diagram draws that ratio as a block. Arrows carry the input and output signals. The reference input (the excitation or cause) passes through that transfer function and becomes the controlled output … Read more
Schering Bridge Theory A Schering Bridge is an AC four-arm network that measures a capacitor’s capacitance and its dissipation factor. The same reading, with known electrode geometry, gives relative permittivity of a dielectric. The Schering Bridge circuit is below.c1 is the unknown capacitance. r1 is its series equivalent loss resistance. c2 is a low-loss standard … Read more
Hay, Maxwell and Anderson already cover much inductor work. Hay’s bridge suits quality factor above 10. Maxwell’s bridge suits Q from about 1 to 10. Anderson bridge covers a wide L span. Owens Bridge is the Owen L-C bridge used when you want that wide L span in terms of a standard capacitor, including incremental … Read more
A servo motor is a closed-loop actuator built around a servomechanism. The loop holds shaft angle, and often speed or torque, to a command. An open-loop DC motor is a poor fit for a control-surface position loop such as an aircraft tail. The pages below cover common places that closed-loop motor shows up. Servo Motor in … Read more
What is Maxwell Bridge A Maxwell Inductance Capacitance Bridge is a four-arm AC Wheatstone bridge used to measure self-inductance by a null. The unknown coil sits in one arm. A parallel resistor and capacitor in the opposite arm make the Maxwell-Wien form. The inductive arm has a lagging phase. The capacitive arm has a leading … Read more
Anderson’s Bridge Anderson’s bridge is the low-Q inductance bridge. Maxwell bridge covers medium Q. Hay’s bridge covers high Q. Maxwell and Hay both struggle to null a low-Q coil. Use Hay for high Q and Maxwell for medium Q. Anderson’s Bridge is a modified Maxwell’s inductance-capacitance bridge with an extra resistor-capacitor path for low Q. … Read more
Earlier pages covered the usual gates in digital electronics: the basic AND gate, OR gate and NOT gates, plus NAND, NOR, XOR and XNOR. An INHIBIT gate adds a control pin that can freeze the output. Designers use that pin when a path must stay quiet unless a separate enable is true.The inhibit pin, when … Read more
A digital integrated circuits logic family is one production style and circuit style that a vendor publishes as a matched set. Parts in that Logic Families group share the same electrical envelope, so one family of ICs can usually plug together without a translator. The shared spec covers supply voltage range, speed class, power, input … Read more