This webpage doesn't work with Internet Explorer. Please use the latest version of Google Chrome, Microsoft Edge, Mozilla Firefox or Safari.
型號需要超過三個文字以上
The information presented in this cross reference is based on TOSHIBA's selection criteria and should be treated as a suggestion only. Please carefully review the latest versions of all relevant information on the TOSHIBA products, including without limitation data sheets and validate all operating parameters of the TOSHIBA products to ensure that the suggested TOSHIBA products are truly compatible with your design and application.
Please note that this cross reference is based on TOSHIBA's estimate of compatibility with other manufacturers' products, based on other manufacturers' published data, at the time the data was collected.
TOSHIBA is not responsible for any incorrect or incomplete information. Information is subject to change at any time without notice.
型號需要超過三個文字以上
In the most basic circuit, op-amps are used as voltage amplifiers, which can be divided into noninverting and inverting amplifiers. In addition, op-amps are also commonly used as voltage followers (also called buffer amplifiers or simply buffers). Op-amps are also used in many other configurations, including differential amplifiers and integrator circuits. Figure 1 shows an example of a noninverting amplifier. Both R1 and R2 are external resistors. In this circuit, negative feedback is used to apply a portion of the output voltage to the inverting input via R1 and R2. The closed-loop gain*1 (GV) of this circuit is expressed only with R1 and R2. The ease of gain setting is one of the advantages of an op-amp.
Figure 2 shows a voltage follower. In the voltage follower, R1 is infinite and R2 is equal to zero. As a result, all of the output voltage is applied to the inverting input. Because V+ and V- are virtually shorted*2, the output voltage is equal to the input voltage.
A voltage follower is commonly used as a buffer since it is useful for impedance conversion because of low output impedance.
Figure 3 shows an inverting amplifier. R1 and R2 are external resistors. As is the case with a noninverting amplifier, an inverting amplifier uses negative feedback. Therefore, the closed-loop gain of the inverting amplifier can be calculated with a simple equation shown in Figure 3.
*1 See the FAQ entry “What are open-loop and closed-loop gains of an op-amp?”
What are open-loop and closed-loop gains of an op-amp?
*2 See the FAQ entry “What is the virtual short of an op-amp?”
What is the virtual short of an op-amp?
The following documents also contain related information: