Position: Index > 555 Circuit >

555 Square wave Generator with a Large-scale Changeable Duty

2015-01-29 10:07  
Declaration:We aim to transmit more information by carrying articles . We will delete it soon, if we are involved in the problems of article content ,copyright or other problems.


555 Square wave Generator with a Large-scale Changeable Duty cycle
555 Square wave Generator with a Large-scale Changeable Duty cycle
Figure 3-5 Square wave Generator Circuit with a Large-scale Changeable Duty cycle As shown in the figure 3-5, 555, R1,R2, RP1, D1,D2 and C1 constitute an astable multi-vibrator. D1 and D2 refer to the guide tubes on the charge and discharge loop respctively. tc=0.693(R1+RPleft)C1 td=0.693(R2+RPright)C1 t=tc+td =0.693(R1+R2+RP)C1 Dmin=tc/T=(R1+R2+RP)≈0.01% Dmax=tc/T=(R1+RP)(R1+R2+RP) ≈99.99% From the formula above we can conclude that, no matter how RP1 is adjusted to, the oscillation period won't be affected. Oscillation frequency of the parameter in the figure is about 20Hz.