Generating electric pulses and amplifying the electric pulses,

Conversion and shaping circuit.

Timer in household appliances,

report

Call the police,

Electronic switch,

Electronic clock,

Electronic toys and electronic medical instruments.

Use a pulse circuit.

Basic knowledge of pulse circuit

1 state and 0 state are represented by high level and low level respectively in digital circuit. At this time, the waveform of the electrical signal is non-sinusoidal. Generally, all voltages or currents that are neither DC nor sinusoidal AC are collectively called pulses.

Figure Z 160 1 shows several common pulse waveforms, which can be repeated periodically or occasionally.

There are many kinds of pulse waveforms, and the parameters that characterize their characteristics are also different. Here, taking the rectangular pulse shown in figure Z 1602 as an example, the main parameters of the pulse waveform are introduced.

(1) pulse amplitude Vm-the maximum value of pulse voltage or current. The units of pulse voltage amplitude are V and mV, and the units of pulse current amplitude are A and mA.

(2) The rising time of the pulse front tr-the time required for the pulse front to rise from 0. 1Vm to 0.9VM .. The units are milliseconds, microseconds and nanoseconds.

(3) the falling time of the pulse trailing edge TF-the time required for the pulse trailing edge to fall from 0.9Vm to 0. 1Vm. Units: milliseconds, microseconds, nanoseconds.

(4) Pulse width tk-a period of time from the pulse rising edge to 0.5Vm to the pulse falling to 0.5Vm, in units of s, ms, μs or ns.

(5) pulse period t- the interval between two adjacent pulses in the periodic repetitive pulse sequence. Units: seconds, milliseconds, microseconds.

(6) Pulse repetition frequency-the reciprocal of the pulse period, that is, f = 1/t, which indicates the number of pulse repetitions in unit time, and the unit is Hz, kHz and MHz.

(7) Duty ratio tk/t- the ratio of pulse width to pulse period, also known as duty ratio.