555 Square wave Generator with a Large-scale Changeable Duty cycle

Published:2011/6/30 0:04:00 Author:Zoey | Keyword: 555 quare wave Generator, Large-scale Changeable, Duty cycle | From:SeekIC

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.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/555_Circuit/555_Square_wave_Generator_with_a_Large_scale_Changeable_Duty_cycle.html

Print this Page | Comments | Reading(3)