Comparator applications

About: Comparator applications is a research topic. Over the lifetime, 2518 publications have been published within this topic receiving 26639 citations.

Fume detector and alarm system

Abstract: A fume detector including a gas sensor having a heater element and a variable impedance element associated therewith whose impedance decreases in the presence of toxic gases or fumes, or a decrease of free oxygen in an atmosphere being monitored A load resistor in series circuit with the gas sensor and a pair of series connected potentiometers in parallel circuit with the gas sensor and the load resistor form a Wheatstone bridge A first voltage comparator connected to one of the potentiometers and a reference voltage provides a signal when the supply voltage decreases below a predetermined level A second voltage comparator connected to the other potentiometer and a junction between the gas sensor and the load resistor provides a signal when the gas sensor fails in the open circuit condition A third voltage comparator connected across the bridge provides a signal when a toxic gas condition exists The first, second and third voltage comparator outputs are commonly connected to the input of a fourth voltage comparator A warning device is connected to the output of the fourth voltage comparator and is energized when any one of the signals of the first, second and third voltage comparators falls below a predetermined level

Differential threshold detector

Abstract: An adaptive reference threshold detector for sensing a drop of predetermined magnitude in the level of an input signal from its peak value during an interval of time A capacitor, diode coupled to the output of a voltage follower, is charged to a level coincident with the maximum input signal voltage during the time interval of interest The voltage stored thereon is coupled through a negative feedback arrangement and resistive divider network to one port of a voltage comparator The input signal itself serves as the second input to this voltage comparator circuit A logic level signal is generated by this comparator when the difference between its two input port signals exceeds a predetermined value

Apparatus for peak detection in magnetic recording

Abstract: An apparatus is disclosed for detecting the peaks of a signal recorded on a magnetic storage medium. An absolute value circuit is used to generate an output that is approximately equivalent to the mathematical absolute value of the raw signal input from the storage medium. The absolute value signal is then coupled to both a differentiator circuit and a noise rejection comparator circuit. A second comparator which detects the zero voltage crossings of the differentiator circuit is enabled and disabled by the output from the noise rejection comparator so that transitions of opposite polarity are produced, corresponding to the peaks and positive going reference level crossings of the raw signal input, while noise on the raw signal input below a qualification level established by the noise rejection comparator circuit is rejected. The output of the second comparator is then coupled to a monostable multivibrator which produces digital pulses of a desired period which correspond to the peaks of the signal record on the magnetic storage medium.

Contactless magnet-activated proportional controller

Abstract: An electrical power controller includes an integrated circuit having a Hall element, a Hall voltage amplifier, a ramp signal generator, and a voltage comparator. The output of the ramp generator is connected to one input of the voltage comparator and the output of the Hall voltage amplifier is connected to the outer comparator input. During intervals when the amplified Hall voltage exceeds the ramp voltage, the output of the comparator changes from one binary state to the other such that a stream of pulses is generated at the output of the comparator. Thus as a magnetic field at the Hall element increases, the Hall voltage increases and the width of each pulse in the stream of pulses grows proportionally. Mechanical means is provided for manually moving and guiding the pole of a magnet along a path toward the integrated circuit. Constructions of such controllers adapted for use as lamp dimmers and DC motor speed controllers are described.

High speed comparator with blocking switches for SAR convertor

Abstract: Open loop common mode driver for switched capacitor input to SAR. A method for controlling the operation of a SAR conversion cycle. The method includes the steps of first initiating the SAR conversion cycle by connecting one side of a plurality of capacitors in a capacitor array to a first capacitor reference voltage and the other side of the plurality of capacitors to the input of a comparator. This is followed by the step of sequentially switching in a plurality of compare cycles the one side of a select one or ones of the capacitors to a second capacitor reference voltage to change the voltage on the input of the comparator. Then, a compare operation is initiated after initiation of each compare cycle to compare the value on the input of the comparator with a compare reference voltage after a predetermined settling time has elapsed from the beginning of the initiation of each compare cycle. During the compare cycle, transients due to voltage variations on the input of the comparator are reduced as a result of the step of sequentially switching, the reduction operating for a predetermined portion of the associated compare cycle.