Friends, I have 4x4 led arrays. At one time 4 leds can be lighted and at another time it may be 8 or even 12. This I am doing with a help of software and pcb. Say like Letters displaying in an led panel.

I have 100Watts bulb (220v AC power supply) on the other side. I want to light these 100W bulbs as according to the LED panel. If 4 leds glow, the corresponding 100W bulbs must glow. If 12 leds glow, the corresponding 100w bulbs must glow.

Please give me some idea.

I worked with 3v dc relay switches. But in vain. I am not getting above 1.5v dc in the led panel. I have searched for 1.5v dc relay, but is not available (only SSR's are available, which is costly)

Can I use a transistor. Please help me. Thanks.

  • 4
    \$\begingroup\$ You need to add the schematic diagram of your circuit. \$\endgroup\$
    – Steve G
    Oct 3, 2016 at 7:30

1 Answer 1


Use the LED voltage for turning on an N channel MOSFET. The MOSFET (and a suitable extra DC supply) can then turn on the appropriate relay and thus activate the lamps.

So, you need MOSFETs and an extra DC supply. If you already have a bunch of 3V relays, the extra DC supply could be 3.3 volts because they are likely to be more common than a 3V supply but please do check the specifications for the relays.


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