Putting aside the embarrassment of asking for a 'simple' solution, I will state in advance that I know I could do this with push-to-make switches and MOSFETs. What I am stuck on is whether I am missing an obvious wiring solution that would have the same effect without parts I don't have currently.

So here's the situation:

I have three LEDs (B1, B2, and B3) in parallel in a circuit powered by a battery. Currently, one switch (S1) turns them all on, and the same switch (S1) turns them all off.

I would like more control over this system, such that B2 has a switch (S2) which ONLY turns B2 on and off, and B3 has a switch (S3) that ONLY turns B3 on and off. So far so simple. The challenge:

I would like S1 to retain the same amount of control that it currently has. So if S1 is on, B1+B2+B3 are on (regardless of the state of S2 and S3), and if S1 is off AND S2 or S3 are on, ONLY B2 or B3 (respectively) are on (in an ideal world, if S2 were already on, S1 were switched on then off, all bulbs would turn off, however I believe this is a logical impossibility)?

I have latching switches, diodes, and wires galore, but no transistors to make this. Is it possible?


2 Answers 2


What about this:


simulate this circuit – Schematic created using CircuitLab

The left schematic is as I interpreted from your description.

  • S1 switches all LEDs on
  • S2 switches only B2 on
  • S3 switches only B3 on

The right schematic is if you'd want to control all LEDs separately.

  • S11 switches all LEDs on
  • S12 switches only B11 on
  • S13 switches only B12 on
  • S14 switches only B13 on

Is usage of diodes acceptable? Is so, then following solution should work (I hope I understood your question correctly):

enter image description here

You can switch all leds with SW1, even if SW2 and SW3 are off, but when SW1 is off then you can turn on LED2 and LED3 separately with SW2 and SW3...


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