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Comparator (pack of 5) £1.55

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Comparator Quad IC LM339

The LM339 consists of four independent voltage comparators that are designed to operate from a single power supply over a wide range of voltages. Operation from dual supplies also is possible, as long as the difference between the two supplies is 2 V to 36 V, and VCC is at least 1.5 V more positive than the input common- mode voltage. Current drain is independent of the supply voltage. The outputs can be connected to other open-collector outputs to achieve wired-AND relationships.

The LM339 is a dual comparator with the ability to operate up to 36 V on the supply pin. This standard device has proven ubiquity and versatility across a wide range of applications. This is due to very wide supply voltages range (2 V to 36 V), low Iq, and fast response of the device. This device is Q100 qualified and can operate over a wide temperature range (-40c to 125c). The open-drain output allows the user to configure the output logic low voltage (VOL) and allows the comparator to be used in AND functionality.

Tech Tin Files: The workings of a comparator (short story)

  • In electronics, a comparator is a device that compares two voltages or currents and outputs a digital signal indicating which is larger. It has two analog input terminals V+, and V-, and one binary digital output Vo. The output is ideally :-
    Vo = 1 if V+ > V-
    Vo = 0 if V+ < V-
  • A comparator consists of a specialized high-gain differential amplifier. They are commonly used in devices that measure and digitize analog signals, such as analog-to-digital converters (ADCs), as well as relaxation oscillators.
  • In theory, a standard op-amp operating in open-loop configuration (without negative feedback) may be used as a low-performance comparator. When the non-inverting input (V+) is at a higher voltage than the inverting input (V-), the high gain of the op-amp causes the output to saturate at the highest positive voltage it can output. When the non-inverting input (V+) drops below the inverting input (V-), the output saturates at the most negative voltage it can output. The op-amp's output voltage is limited by the supply voltage.