I have an AC indicator lamp which I have to add to a design and and here is the only information.

enter image description here

As you see the two terminals are tied on one side and the other two pins has no continuity with any other pins. I cannot verify the correct phase and neutral pins.

Is the upper two(silver like) neutral and the bottom gold like color is for line? What can be the reason there are four pins?

I measure the resistance infinity but shouldn't it be 230/3mA = 76kOhm? I measure between the golden and the silver pins.

  • 1
    \$\begingroup\$ I measure the resistance infinity but shiouldnt it be 230/3mA = 76kOhm? No as it is very likely that the indicator is a neon lamp. This will only "strike" and conduct current when the voltage is high enough. Your multimeter's voltage is too low for that to happen (luckily) so you measure an open. \$\endgroup\$ – Bimpelrekkie Oct 30 '18 at 12:07
  • \$\begingroup\$ My other problem is the golden color pins are not giving continuity. The silver ones are connected to each other. So makes me confused abut what is going on internally. Can I connect any golden to line and silver to neutral? \$\endgroup\$ – cm64 Oct 30 '18 at 12:34
  • \$\begingroup\$ Do you have the rs reference? Perhaps you are dealing with a bicolor or tricolor lamp \$\endgroup\$ – David Oct 30 '18 at 12:34
  • \$\begingroup\$ I could only find this docs-emea.rs-online.com/webdocs/1578/0900766b81578e19.pdf \$\endgroup\$ – cm64 Oct 30 '18 at 12:36
  • \$\begingroup\$ @Bimpelrekkie The datasheet given says that it's an LED lamp, not neon. \$\endgroup\$ – Hearth Oct 30 '18 at 12:43

I suggest you contact the (real) manufacturer (or design owner) and ask if you don't feel like figuring it out for yourself (if you are 100% comfortable poking around with mains voltage just use a series resistor and you won't harm the lamp- if you are not comfortable get someone else local to help so you don't harm yourself).

Clearly the mains voltage will be applied on opposite sides of that barrier! So that narrows it down to the commoned terminals and one of the other terminals.

This is an LED lamp, probably with a high value series resistor and maybe a half-wave series diode.

My guess:


simulate this circuit – Schematic created using CircuitLab

It could be a capacitive dropper too but the German documents show AC/DC compatibility which points to a resistor.

The manufacturer appears to be:

Signal Construct GmbH

Brückenäckerweg 4 D-75223 Niefern-Öschelbronn

Tel. (49) 7233 / 9531-0 Fax (49) 7233 / 9531-29

E-Mail: info@signal-construct.de

Web: http://www.signal-construct.de


N 048° 54´ 03,4"

E 008° 48´ 31,1"

I think the actual part number is 22H0289. A pox on distributors who hide manufacturer's information.


The data sheet shows the leads for each termination configuration, and for all the other terminations the anode/positive is the top lead (red or longer) so I would be surprised if the brass lugs are not the anode and the tinned lugs the cathode in the DC variants.

As yours is the AC variant, and assuming it's got two LEDS in different directions, diodes to prevent backward voltage getting too high and resistors for current limiting, it should start glowing with a few volts DC across it. The forward voltage of the diodes could mess up multimeter resistance readings. I'd guess that each of the tinned pins corresponds to one LED and you can either connect it for either full wave or half wave.

  • \$\begingroup\$ But I apply 9V DC from a battery between a golden pin and the silver and there is no glow. \$\endgroup\$ – cm64 Oct 30 '18 at 12:39
  • \$\begingroup\$ The twp golden pins next to eachother does not give continuity. Could you add a diagram how inners might look like? \$\endgroup\$ – cm64 Oct 30 '18 at 12:41
  • \$\begingroup\$ Here's an example of what that circuit could be like: schematics.dapj.com/2004/11/… Note that there is a capacitor (C1) in series and that will prevent the LED to light up for any DC voltage. The circuit needs AC and high voltage. \$\endgroup\$ – Bimpelrekkie Oct 30 '18 at 13:04

The lamp is red.

Source: RS.

Extra positive terminal for lamp test facility

2 negative terminals allow "daisy chaining" 0.11in. (2.8 x 0.8mm) terminals.


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