How to use a 555 timer to generate a square wave generator with 1Hz pulses

The principle is to boost the voltage after the DC power is oscillated. For example, a low-power electric baton can generate a high-voltage pulse using a 6V-12V DC power supply. In the circuit, the transistors Q1 and Q2 constitute an oscillator, which generates a DC pulse voltage with a frequency of 3Hz, and the input transformer ratio is 6V: 240V The primary coil of the booster, at the end of each pulse, correspondingly in the secondary of the transformer. The coil generates a high voltage. The repetition frequency of the pulse can be adjusted by selecting the value of C2 and R1.

555 timer as a second pulse generator with a frequency of 1Hz

The principle is to boost the voltage after the DC power oscillates. For example, a low-power electric baton can generate a high-voltage pulse using a 6V-12V DC power supply. In the circuit, the transistors Q1 and Q2 constitute an oscillator, which generates a DC pulse voltage with a frequency of 3Hz, and the input transformer ratio is 6V: 240V The primary coil of the booster, at the end of each pulse, correspondingly in the secondary of the transformer. The coil generates a high voltage. The repetition frequency of the pulse can be adjusted by selecting the value of C2 and R1.

As shown below:

  How to use a 555 timer to generate a square wave generator with 1Hz pulses

1.Second signal generator circuit

The second signal generating circuit is composed of a multivibrator composed of an integrated circuit 555 timer and RC. The required chips are the integrated circuit 555 timer, as well as resistors and capacitors. The following figure is its circuit diagram:

 How to use a 555 timer to generate a square wave generator with 1Hz pulses

The oscillator circuit is the core part of the digital clock, and its frequency and stability are directly related to the accuracy of the watch. Therefore, a multivibrator composed of a 555 timer is selected, in which the capacitor C1 is 47 microfarads, C2 is 0.01 microfarads, and the two resistors R1=R2=10K ohms. At this time, a periodic rectangular wave is obtained at the output end of the circuit, and its oscillation frequency is:

f=1.43/[(R1+2R2)C](3-1)

Substitute the values ​​of R1, R2 and C by formula (3-1), f=1Hz.That is, its output frequency is a rectangular wave signal of 1Hz

2. Use 555 to make a second pulse

The output frequency is 1Hz and the duty cycle is 50%

  How to use a 555 timer to generate a square wave generator with 1Hz pulses

Since CD4060 cannot be simulated in MULTISIM, this design uses three 74HC161 and one 74HC160IC in cascade to form a 2^15 frequency divider. The unit circuit connection is shown in the following figure:

 How to use a 555 timer to generate a square wave generator with 1Hz pulses

3. Design of second square wave generator based on NE555

The NE555 chip and the peripheral circuit are used to build a multivibrator, and the output square wave frequency is 1Hz by designing the parameters of the peripheral circuit, so it is called the second square wave generator. Since the duty cycle of the pulse has little effect on the system, the duty cycle is designed to be 1/3. The output square wave is used as the clk signal of the counter and D flip-flop. The NE555 timer pin diagram is shown in Figure 1, the pulse frequency formula:

f=1/(R1+2R2)CR2

Select R1=47K, R2=47K, RV1=2K, C=10μF to form the circuit diagram as shown in Figure 2:

How to use a 555 timer to generate a square wave generator with 1Hz pulses

 How to use a 555 timer to generate a square wave generator with 1Hz pulses

Existing 0.01uF 1uF 10uF capacitors each, two 6.8k 1k 330 ohm resistors, how to use 555 to generate 1Hz square wave pulse

  How to use a 555 timer to generate a square wave generator with 1Hz pulses

R1 uses 330 ohms, R2 uses 6.8K ohms, C uses 0.1uF555 pin 3 output square wave period T=0.7 (R1+2R2) C=0.7x (0.33+2×6.8) x0.1 =0.9751

Square wave frequency F=1/T=1/0.9751=1.0255Hz

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