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10 Threads found on 555 Variable Duty Cycle
Actually, I want to use only one POT to change the frequency such that the duty cycle should remain fixed. Can't be easily achieved with a 555. A standard OP generator can do it, see post #2. Asymmetrical thresholds set the intended duty cycle, a single potentiometer the time comstant.
I don't agree about "unusual". A 555 circuit with feedback from output instead of DISCHG pin can be already found as 50 % duty cycle oscillator in the LMC555 datasheet. The variant with diodes and variable duty cycle is at least frequently used.
Hi i would like to make an frequency generator using a 555 timer chip. The frequency should vary in the range of 100hz to 1kHz with a reasonable duty cycle (20-80%). I am using the circuit below. Varying r2 alone would not do the job because at r2=0 the duty cycle is 100%. I found out if i started (...)
What will happen ???!!!!! what do you mean by that ? what do you want to do exactly ? you have a 555 TIMER , if you set it as A stable , it will work and oscillate as well . if you change D.C no thing special will happen . i don't know what is your exact aim .
Dear vead Hi It is a very sweet and easy project ! at first try to generate a variable duty cycle square wave . e.g with 555 . if you can do it , tell me , i'll illustrate you another step . Best Wishes Goldsmith
You can use a 555 timer in astable mode. You can find a schematic and calculator here . variable period and duty cycle can be achieved by using variable resistors and capacitors. You may also need to use the CONTROL pin.
hi in simple way u can use 2*(555) timer first one as stable the output of first one trigger second 555 connected as monostable and last one drive output stage with that connection u can adjust period and pulse width for drive signal
Hi I need to generate PWM signal for battery powered application to make ON/OFF for a swicth.The frequency is typically 1 second and I need to have a variable duty cycle by means of POT. I did look into 555 and 556 timer circuts and op amp PWM geneartion cicuits . It looks they all consume much current. Since it is (...)
You will not get a symmetric square wave with only the 555 (50% duty cycle) and a variable output frequency will change the duty cycle also. Try another IC like XR2206.
Hi, I am new in this forum and I am a beginner with electronics... I wont to pilot and variate the power a 12 volt 5w lamp. If I use a bd 649 it becomes very hot. I have also tryied win a 2n3055 (15 ampere.......). I wont to pilot the final with a 555 with a variable duty cicle, for slowly power off the lamp. Is the best thing? How conntect (...)