Simple astable multivibrator circuit using CD4047 Cmos IC
When we say to the an astable multivibrator circuit, Many people will think to Many people think of as the most IC-555. But this time, it is recommended circuit in Figure 1. Which use IC-4047 CMOS with ability of this nature as well. And the advantage is, That output will be a square wave, which has three forms are: First at pin 13 of IC1 will be basic frequency, Second is pin 11 will be Is half that of basic frequencies, And thirdly at pin 10 is half the frequency of basic frequency. but will has to invert the signal to 180 degrees. So is there a characteristics opposite to the second output.
This circuit yet cannot adjust duty cycle. So sorry, if one were to try to use the adjusted duty cycle. But output of IC will have duty cycle of 50% makes has symmetry exists. For the controller frequency will be serves as VR1 and C1. By the value of VR1 is used in a range of 1 KHz to 1 MHz. To Adjust to the desired frequency. The C1 will determine the frequency. The value used to determine the various range. Can see from the table below. And should select capacitors that have low leakage.To waveform distortion and frequency can not be much.
The value of C1 in circuit as Figure 1 to determine the frequency use.
1uF = 1-10Hz
0.1uF = 10Hz-1kHz
0.01uF = 100Hz-10kHz
How to builds
This project is a few components so can put on the universal PCB board as Figure 2. And be carefully for wiring,the polarity of the electrolytic capacitors, Pin of the IC.
Figure 2 the components layout of this projects
VR1______See in text
C1_______See in text
IC1______CD4047____Low Power Monostable Astable Multivibrator
Socket 14 pin, The universal PCB board.