Hello everyone
I want to rectify a half-wave using a thyristor and trigger it using a 555 timer using the Proteus program, but I cannot. Can someone help me?

 

You need a zero-cross detector and monostable made from 555 that triggers SCR after certain time.

What Ac voltage? What load?

 

This is the problem ,I did't know how to connect it to the source and timer

 

If the load can be on high-side you can trigger the SCR with 555 directly:


Otherwise (load on low-side) you need a small transformer for triggering. Or auxiliary (isolated) power source + optocoupler.

 

bro, can you take a look,

 

The reason of RC derivative after 555 is the SCR should be triggered with very short pulse.
If the frequency of AC is 50Hz (20ms period) the trigger pulse width to SCR gate should be about 100us.
If the Rg in gate is 100 ohm pick the C about 470nF and the bottom R=1k.

Btw, since the 555 outputs positive pulse you need to place a NOT gate after it. So the trigger pulse to SCR is generated after 555 falling edge (the NOT gate rising edge):


An option to get rid of NOT and RC is to use a next 555 monostable generated a 100us positive pulse for triggering the SCR.

 

Maybe that will help:

Download this working project, open it in Proteus,
and rebuilt it as you want:
https://forum.allaboutcircuits.com/attachments/test1-fixed-zip.267529/

https://forum.allaboutcircuits.com/...it-not-working-in-proteus.186554/post-1733795

 

Thank you, my friend, but I want it exclusively through the thyristor because I want to print the circuit

 

Hello everyone
I want to rectify a half-wave using a thyristor and trigger it using a 555 timer using the Proteus program, but I cannot. Can someone help me?

What Thyristor? SCR or Triac?
For a Half Wave, you need a SCR, not a Triac. You can, of course, use the Triac as a SCR.
Do you want to use the SCR as a Diode or do you want to use it for voltage control?

 

Half Wave using SCR and trigger it using a 555 timer and pcb

 

Could you take a look at the file please

 

The reason of RC derivative after 555 is the SCR should be triggered with very short pulse.
If the frequency of AC is 50Hz (20ms period) the trigger pulse width to SCR gate should be about 100us.
If the Rg in gate is 100 ohm pick the C about 470nF and the bottom R=1k.

Btw, since the 555 outputs positive pulse you need to place a NOT gate after it. So the trigger pulse to SCR is generated after 555 falling edge (the NOT gate rising edge):

View attachment 336054
An option to get rid of NOT and RC is to use a next 555 monostable generated a 100us positive pulse for triggering the SCR.

Could you have a look at the file please

 

Could you have a look at the file please

Sorry , I don’t have Proteus installed. Paste a screen here.

 

Sorry , I don’t have Proteus installed. Paste a screen here.

The problem is that it never gives me an output signal, and most likely I don't know how to connect the 555 to the detector and create a trigger.

 

This is 555 monostable. It is triggered by pulling pin2 low. There are plenty of calculators on internet to obtain R and C for desired timing.

 

This is 555 monostable. It is triggered by pulling pin2 low. There are plenty of calculators on internet to obtain R and C for desired timing.

View attachment 336155

Look at this wave

 

This is 555 monostable. It is triggered by pulling pin2 low. There are plenty of calculators on internet to obtain R and C for desired timing.

View attachment 336155
I want to ask you if the detector is connected correctly like this

 

You are just shorting the DC power supply with optocouplers transistor. It doesn’t trigger the 555.

Remove the push button and use 2n7000 transistor instead:
(Note: I didn’t draw the parts around 555.)

 

You are just shorting the DC power supply with optocouplers transistor. It doesn’t trigger the 555.

Remove the push button and use 2n7000 transistor instead:
(Note: I didn’t draw the parts around 555.)

View attachment 336259

I put the load from the bottom and I got this signal but there is still a little bit at the bottom. What do you think is the problem?
note:
Yellow line before resistance
The blue line is after the resistance

Purple line outpot

 

Half Wave using SCR and trigger it using a 555 timer and pcb

Why do you need a 555 timer for triggering a SCR?