1
\$\begingroup\$

I want to make a simple ladder circuit to control the on and off of a light bulb using 2 switches, but I am going to manipulate one of the switches by means of a microcontroller, and also I don't want to use a relay because they wear out with time. I am trying with this circuit with optocouplers, a pnp transistor and triacs, as seen in the image, but it does not work well, also when I am simulating it in proteus 8.9 after a certain time it throws me these errors:

[SPICE] DELMIN increased to 8.88178e-016 due to lack of time precision [SPICE] transient GMIN stepping at time = 6.54158 [SPICE] TRAN: Timestep too small; timestep = 1.11022e-016: trouble with node # $ IAC AMMETER # 0020_AVS1 # AB # branch.

enter image description here

I don't know what I'm doing wrong, I already tried it on a breadboard and it doesn't work either.

If someone can help me or suggest another circuit that works for what I need, I appreciate it a lot and forgive my English.

\$\endgroup\$
4
  • \$\begingroup\$ You are trying to drive your triacs from a 5 volt supply (V2) and this won't work because the triac circuit is not sharing the same ground as your 5 volts. You need a proper triac driver circuit and not guesswork. \$\endgroup\$ – Andy aka Dec 7 '20 at 14:45
  • \$\begingroup\$ Under the AC 120V 60Hz power supply next to the light bulb, I put the ground 5V (V2), I am sharing it with the neutral of the AC signal, that is, if they share the same ground. Or am I doing it wrong? \$\endgroup\$ – andresuarez_95 Dec 7 '20 at 14:55
  • \$\begingroup\$ The GND of your digital circuit should not be common to AC neutral. That's incredibly dangerous. \$\endgroup\$ – BB ON Dec 7 '20 at 15:12
  • \$\begingroup\$ Sorry, I'm not an electronics expert, but I understand that if GND can be shared, for that reason I did so. So how can I do it? \$\endgroup\$ – andresuarez_95 Dec 7 '20 at 15:18
2
\$\begingroup\$

Use a solid state relay (SSR)

Some examples include...
AQH3223 , 600V, 1.2A, DIP-8
https://b2b-api.panasonic.eu/file_stream/pids/fileversion/2787

CPC1976Y , 600V 2A, AC Zero Cross, SIP-4
https://www.ixysic.com/home/pdfs.nsf/0/8471676520A90EC185256F5600507F99/$file/CPC1976.pdf

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.