The general, standard component types that you are looking for are more precisely termed "ideal diode," and "ideal opamp." Ideal Components may be used to represent real electrical components, and do not exist in the real world. Analytical equations and intuition are often greatly simplified by using idealized components instead of more realistic models. When discussing or simulating circuits on an ideal level, there should be no specific device or model number that comes to mind. When people say "use an opamp" in a theoretical setting they are usually referring to an ideal opamp. This is what it means when we say "ideal opamp":
Ideal opamps
An ideal opamp is usually considered to have the following properties:
- Infinite open-loop gain
- Infinite voltage range available at the output
- Infinite bandwidth with zero phase shift and infinite slew rate
- Infinite input impedance and so zero input current and zero input offset voltage
- Zero output impedance
- Zero noise
- Infinite Common-mode rejection ratio (CMRR)
- Infinite Power supply rejection ratio.
These ideals can be summarized by the two "golden rules":
- The output attempts to do whatever is necessary to make the voltage difference between the inputs zero.
- The inputs draw no current.
The first rule only applies in the usual case where the op-amp is used in a closed-loop design (negative feedback, where there is a signal path of some sort feeding back from the output to the inverting input). These rules are commonly used as a good first approximation for analyzing or designing op-amp circuits.
None of these ideals can be perfectly realized. A real op-amp may be modeled with non-infinite or non-zero parameters using equivalent resistors and capacitors in the op-amp model. The designer can then include these effects into the overall performance of the final circuit. Some parameters may turn out to have negligible effect on the final design while others represent actual limitations of the final performance that must be evaluated.
This diagram shows an equivalent circuit of an operational amplifier that models some resistive non-ideal parameters. From the ideal opamp properties above, an ideal opamp would have:
- \$ R_{in} = \infty \$
- \$ R_{out} = 0 \$
If you are using a tool such as PSPICE, there is usually an ideal opamp model (maybe OPAMP). If not, it is quite simple to build one using idealized components. Don't forget that real op-amps differ from the ideal model in various aspects.
Keep in mind the distinction between ideal circuit models and realistic circuit models. All basic electronic components have some ideal model that can be used for simplicity. If the component has a model number, it models a real component rather than an ideal component. Usually design tools name ideal models with the generic name, e.g. "RESISTOR," "CAPACITOR," "OPAMP," etc.
Source: diagram and explanatory text from Wikipedia.
