Making PWM controlled 12V light dimmer

Thread Starter

Djordje Djozlija

Joined Feb 2, 2020
4
Hi, have project in my university, sry for bad grammar.
I need to make pwm signal using 555timer for 12V light bulb, but it has to be oscillator controlling 555 timer so the bulb is continuously fading and lighting up again, my teacher said i should make a oscillator using a buffer and integrator for the control signal, plus i have to use one potentiometer to adjust period of lighting and fading the bulb. Can anyone help me by sending me some useful links so i can explore it more, or give me some useful information on the matter, also the teacher sad i should use LM324 because it has 4 op amps.
Thanks
 

ci139

Joined Jul 11, 2016
1,177
I have to make a pwm signal using the 555 timer
// if fixed frequency https://www.homemade-circuits.com/pure-sine-wave-inverter-circuit-using/ ← IC1 IC2(control voltage input to the pin-5)
for the 12V light bulb , // ? wattage
but it has to be the oscillator controlling the 555 timer , so the bulb is
continuousely fading and lighting up again .
For the control signal I should make an oscillator , using the buffer and the integrator , // tri-wave circuit op amp - Google Search
plus i have to use a potentiometer to adjust the lighting and fading period of the bulb. // feed in to the integrating cap.

Can anyone help me by sending me some useful links so i can explore it more ,
or give me some useful information on the matter ,
also i have to use LM324. // ? also 12V or other
 
Last edited:

Thread Starter

Djordje Djozlija

Joined Feb 2, 2020
4
Ive found this, and i think this should be it, how do i make this circuit, what do i feed into input of 555 timer and how to make that green line like a reference voltage to automate pwm.
 

Thread Starter

Djordje Djozlija

Joined Feb 2, 2020
4
Ive found this, and i think this should be it, how do i make this circuit, what do i feed into input of 555 timer and how to make that green line like a reference voltage to automate pwm.
I have to make a pwm signal using the 555 timer
// if fixed frequency https://www.homemade-circuits.com/pure-sine-wave-inverter-circuit-using/ ← IC1 IC2(control voltage input to the pin-5)
for the 12V light bulb , // ? wattage
but it has to be the oscillator controlling the 555 timer , so the bulb is
continuousely fading and lighting up again .
For the control signal I should make an oscillator , using the buffer and the integrator , // tri-wave circuit op amp - Google Search
plus i have to use a potentiometer to adjust the lighting and fading period of the bulb. // feed in to the integrating cap.

Can anyone help me by sending me some useful links so i can explore it more ,
or give me some useful information on the matter ,
also i have to use LM324. // ? also 12V or other
 

Thread Starter

Djordje Djozlija

Joined Feb 2, 2020
4
Thank you for you reply, ive found this circuit on google, my point is, the output from the U1D is the reference voltage to the comparator U1C, but then i will deteremine the speed of the fan ( or in my case the brightness of a bulb), can i somehow make so that reference voltage is always going up and down by itself, so the fan is continously is slowing down and speeding up, only thing i need to do in my case is to set the period of one full lighting and fading of the bulb, my professor said T(period) should be 5s<T<5m, so if the period is 5 min, that means 5 minutes must pass that bulb is slowly turned on and off 1 time.
 

Dodgydave

Joined Jun 22, 2012
8,807
Yes use a 555 timer as an Astable, and feed pin 6 from the 555 into pin 12 of U1D, the Sawtooth wave will go from 4V to 8V...waveforms-tim47.gif
 
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