Need to make this AC circuit 'SAFE'

[acaris]

Hey guys I am trying to build a quiz buzzer / lockout circuit, and came across this

**broken link removed**

1. It looks simple but is it safe? What can i add to make it safer?
2. How can I add bulbs for more contestants?


Thanks in advance

 

[jony130]

Simply build this safe version

 

[acaris]

Hello

Thanks for the reply but we need to have bright lighting, at least a 15 W bulb...is there a solution for tht?

 

[betwixt]

The original schematic is certainly NOT safe if connected to the incoming AC supply. It can be made safer by using a 1:1 isolating transformer and earthing the top line of the circuit but there could still be dangerous voltages on the switch contacts.

Unfortunately, this kind of circuit does not lend itself to having more switches and lamps.

Brian.