Can I replace the potentiometer in this AC dimmer circuit with a fixed resistor so that I can get a permanent dim setting?. If yes then how.

enter image description here

Components in this circuit are The parts used are

WH149-500k potentiometer DB3 bidirectional diode 2k resistance 0.25W MAC97A6 104 630V CBB capacitor

Edit. here is the picture of the pcb kit. The pot has 4 legs?? enter image description here

Edit. I'm adding another circuit which should be clearer. enter image description here

  • 2
    \$\begingroup\$ Sure, set the pot where you want, remove it from the circuit, measure its resistance, replace with closest standard value resistor. \$\endgroup\$ – John D Aug 26 '17 at 18:11
  • \$\begingroup\$ But what should I do with the third leg of the pot? \$\endgroup\$ – Kokachi Aug 26 '17 at 18:14
  • \$\begingroup\$ You have to measure the pot from the wiper to the right end as shown in your schematic. Then the fixed resistor goes between the triac and the right side connection. you don't need the wiper connection, but it's already connected to the triac end anyway. \$\endgroup\$ – John D Aug 26 '17 at 18:17
  • \$\begingroup\$ ok, I can measure the resistance part but the pot has 4 legs. I've added a new picture. Also here is the product information page with more pictures link \$\endgroup\$ – Kokachi Aug 26 '17 at 18:21
  • \$\begingroup\$ A pot typically has 3 terminals. I can't tell what your fourth terminal is. You have to figure out which terminals correspond to the 3 points shown in the schematic and measure and wire accordingly. \$\endgroup\$ – John D Aug 26 '17 at 18:25

If you want to maintain the capability to turn the light fully off you will want to either retain the switch part of the pot (that is the two terminals that stick out the back of the pot) then it does not make sense to remove the entire pot.

This portion of the schematic represents the On/Off switch in the POT.

enter image description here

I did not study the PC board artwork configuration but appears that the side of the POT switch that is away from the AC Line is internally connected to these terminals of the circuit diagram:

enter image description here

  • \$\begingroup\$ I do not want on off function, I want the lamp to always run at 50% dim. The circle with an an X was the 4th leg?? I thought that symbol represented the lamp. \$\endgroup\$ – Kokachi Aug 26 '17 at 19:26
  • \$\begingroup\$ Ok I managed to find out another diagram which is more precise. Here it is, I think it shows the switch. \$\endgroup\$ – Kokachi Aug 26 '17 at 19:27

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