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This op amp was based on a descendant of Loebe Julie's 1947 design and, along with its successors, would start the widespread use of op amps in industry. GAP/R model P45: a solid-state, discrete op amp (1961). 1961: A discrete IC op amp. With the birth of the transistor in 1947, and the silicon transistor in 1954, the concept of ICs became a ...
For amplifiers with both positive and negative power supplies (with respect to earth, as op-amps often have), the PSRR for each supply voltage may be separately specified (sometimes written: PSRR+ and PSRR−), but normally the PSRR is tested with opposite polarity signals applied to both supply rails at the same time (otherwise the common-mode ...
Low-power dual op-amps and comparator [19] LM432 LM358, LMV431 Dual op-amps with fixed 2.5 V reference [20] LM611 Op-amp with an adjustable voltage reference [21] LM614 Quadruple op-amps with an adjustable voltage reference [22] LM675 Power op-amp with a maximal current output of 3 amperes [23] LM709 Yes General-purpose op-amp [24] LM741 LM709 ...
Referring to the above diagram, if the op-amp is assumed to be ideal, then the voltage at the inverting (-) input is held equal to the voltage at the non-inverting (+) input as a virtual ground. The input voltage passes a current V in / R 1 {\displaystyle V_{\text{in}}/{R_{1}}} through the resistor producing a compensating current flow through ...
For transistors, the current-gain–bandwidth product is known as the f T or transition frequency. [4] [5] It is calculated from the low-frequency (a few kilohertz) current gain under specified test conditions, and the cutoff frequency at which the current gain drops by 3 decibels (70% amplitude); the product of these two values can be thought of as the frequency at which the current gain ...
Figure 1: A version of the Widlar current source using bipolar transistors. Figure 1 is an example Widlar current source using bipolar transistors, where the emitter resistance R 2 is connected to the output transistor Q 2, and has the effect of reducing the current in Q 2 relative to Q 1.
Class-A amplifiers may be used in output stages of op-amps [11] (although the accuracy of the bias in low cost op-amps such as the "741" may result in class A or class AB or class B performance, varying from device to device or with temperature). They are sometimes used as medium-power, low-efficiency, and high-cost audio power amplifiers.
where Z dif is the op-amp's input impedance to differential signals, and A OL is the open-loop voltage gain of the op-amp (which varies with frequency), and B is the feedback factor (the fraction of the output signal that returns to the input). [3] [4] In the case of the ideal op-amp, with A OL infinite and Z dif infinite, the input impedance ...