Electrical4U 
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
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
SSI and MSI chips still ship logic gates, flip flops, counters, multiplexers and demultiplexers. Those parts sit at small-scale and medium-scale integration. TTL and ECL used too much area and power for early MOS-scale LSI. CMOS later became the VLSI family. In the MOS-LSI years the dense options were PMOS, NMOS and bipolar I2L. This … Read more
A Schmitt Gates device is a logic gate whose input uses two trip points instead of one. Ordinary gates switch at a single threshold voltage for both rising and falling edges, somewhere between a valid low and a valid high. A slow or noisy edge that lingers near that one trip point can make the … Read more
A logic gate is a digital circuit whose output follows a Boolean function of its inputs. Earlier pages covered the internals of digital logic gates. This page covers common applications of logic gates that follow from that truth table. OR combines trips. AND acts as an enable or inhibit. XOR and XNOR handle parity. NOT … Read more