# I have problem happen lot of times with this circuit

#### pauloDNS

Joined Jul 19, 2020
25

I have this circuit and the signal lamp always burns with two or three months of use, does anyone know why?

#### Attachments

• 169.1 KB Views: 13
• 312 bytes Views: 11

#### AlbertHall

Joined Jun 4, 2014
12,267
What kind of lamp is it - incandescent, led, or...
What is it's rated voltage and what voltage are you applying to it?

#### Ya’akov

Joined Jan 27, 2019
8,160
Without further information, at a guess, I would say you need a fly back diode on the relay coil.

#### AlbertHall

Joined Jun 4, 2014
12,267
Without further information, at a guess, I would say you need a fly back diode on the relay coil.
Yes, if it is an LED. No, if it is incandescent.

#### Ya’akov

Joined Jan 27, 2019
8,160
Yes, if it is an LED. No, if it is incandescent.
If it is a poorly chosen incandescent, the back EMF pulse could kill it as the filament weakens.

#### Dodgydave

Joined Jun 22, 2012
10,946
I would say back emf from the relay K1 is causing the bulb to blow, try using a Neon .

#### AlbertHall

Joined Jun 4, 2014
12,267
I would say back emf from the relay K1 is causing the bulb to blow, try using a Neon .
A neon is no use at 24V.

#### KeithWalker

Joined Jul 10, 2017
2,872
If a flyback diode does not solve the problem, replace the lamp with a LED and suitable series resistor.

#### Dodgydave

Joined Jun 22, 2012
10,946
A neon is no use at 24V.
Where does it say he's using 24V?

The drawing shows L & N.. which suggests that the voltage 120/230AC.

#### sagor

Joined Mar 10, 2019
860
Where does it say he's using 24V?

The drawing shows L & N.. which suggests that the voltage 120/230AC.
His second, attached schematic shows +24V with similar circuit. So which is it, 24V or Line voltages? Hence the ambiguity in the question.

Joined Jul 18, 2013
27,613
If it is the 24vdc circuit, most indicators are now LED and are very reliable, it shows simple contact closure with no Inductor in the circuit.
If the AC version, If there is a spare contact switch it separately, or place an R/C snubber across the coil.