1.？ If an electronic component works without any form of power supply inside, it is called a passive device.

2.？ From the circuit nature, passive devices have two basic characteristics:

(1) It either consumes electric energy or converts electric energy into other energy in different forms;

(2) It can work normally only by inputting signals and without external power supply.

3.？ Passive devices in electronic systems can be divided into circuit devices and connecting devices according to their circuit functions.

(1) Circuit devices: diode, resistor, resistor group, capacitor, inductor, transformer, relay, button, buzzer, horn and switch;

(2) Connecting equipment: connectors, sockets, connecting cables and printed circuit boards.

Basic definition of active devices:

1.？ If an electronic component has an internal power supply when working, it is called an active device.

2.？ As far as circuit characteristics are concerned, active devices have two basic characteristics:

(1) itself consumes electricity;

(2) In addition to the input signal, there must be an external power supply to work normally.

3.？ Active devices are the main devices in electronic circuits. From the physical structure, circuit function and engineering parameters, active devices can be divided into two categories: discrete devices and integrated circuits.

(1) Discrete devices: bipolar transistor, field effect transistor, thyristor, semiconductor resistor and capacitor;

(2) Analog integrated circuit devices: integrated operational amplifier, comparator, logarithmic and exponential amplifier,? Analog multiplier/divider, analog switch circuit, pll circuit (phase locked loop),? Integrated voltage regulator? Reference power supply, waveform generator and power amplifier;

(3) Digital integrated circuit devices: basic logic gates, triggers, registers, decoders, data comparators, drivers, counters, shaping circuits, programmable logic devices, microprocessors, single-chip computers and dsp devices.

Extended data:

The difference between active devices and passive devices

Passive components are mainly resistive, inductive and capacitive components, which are unique in that they can work when there is a signal without adding power to the circuit.

Active components are the core of electronic circuits, and all oscillation, amplification, modulation, demodulation and current conversion are inseparable from active components.

The key to distinguish active devices from passive devices lies in whether the port characteristics of devices depend on external driving sources and whether they are active devices, taking ideal devices as the basis of consideration and avoiding the interference of process factors. For indivisible combined elements, if there are active devices in the combination, the whole is considered as "active".

The so-called "external characteristic" is to describe a certain relationship quantity of the device, although the relationship is described by voltage or current, electric field or magnetic field pressure or speed. The external characteristics of passive devices have nothing to do with whether they exist as driving sources or not.

The concepts of passive and active exist not only in electrical components, but also in mechanical, fluid, thermal, acoustic and other fields.

References:

Baidu encyclopedia-passive equipment

Baidu encyclopedia-mobile equipment