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Could you help me identify the 2 red electrical components on this circuit board and tell me what they do . ( bottom 2 pictures ) http://www.1carpc.co.uk/wcdr/members-temp-pic.htm

Many thanks

Wizard

Hi Wizard,

They look like capacitors to me. In simple terms a capacitor is a kind of electrical storage device. Google it for a proper definition!

David.

According to OH, they are capacitors.   They prevent DC from flowing, but high frequency AC will flow.

They are normally used to remove high frequencies from a low frequency signal, i.e. removing damaging spikes.  To understand what they are doing in this case you need the circuit diagram.

What is the picture of?

Their polyester encapsulated capacitors, the value is 104k. at 400 volt. 

The 4 means 4 more zeros so 100,000pf (picafarad), or another way, move the decimal point back 4 places so 0.1 and that will be 0.1uf (microfarad)

Thanks for the info , it's a hookup Live / Neutral switch box ( for when mains live neutral connections are reversed at the site bollard ) .
The 2 capacitors have mains ( either live or neutral ) going in one end , out the other end to some resistors then thro a rectifier diode to 2 Leds , one red, one green.
The idea is that the Green led lights if the supply is the right way round , and the red if it's not . Then you throw a switch if the red Led is lit . The problem is one ( maybe 2 ) of the components is faulty , and is causes both Leds to light , no matter which way the switch is .

atb

Wizard    

We had an interesting situation last week in France

My Martindale type of tester showed everything OK on my van and another one  but a W4 tester showed mine OK but no earth on the other van

We were plugged in to the same box

The mains lead checked out for earth continuity

Very strange

I wondered what it was, the diodes are 1N4005 so they are 600V

The 'hump back' on the first cap gives the clue, their not made like that so its suffered some shock, I'd just replace them and definitely the diodes, the resistors look fine but the outer ones should be 10k and the middle one 1.5k

You should get both from Maplins for pence, but that's old kit so the new caps will probably be smaller

Thanks Gary  .
I've looked on the Maplins website , but can only find 1N4005S and not 1N4005 , could i use the 1N4005S ?
Will do as you recommend , replace both caps , diodes , will also change resistors.
There is a buzzer connected to the board ( black and red wires ) , will this make a difference to the resistors used .

atb

Wizard

I wouldn't buy resistors from Maplin? I'd never trust them again and I doubt theres anything wrong with the originals anyway and yes, the 'S' is un-important as far as your concerned.

As it happens the 50v version, 1N4001 is the most used component in the world

Thanks mate , i'll go down now, i'll just get the caps and diodes .

atb

Wizard

Thanks for all the help , i now have a repaired and working switch over box , my next project is to see if i can make it automatic , so when the red led lights, it switches a relay that will then do the change over for me .

atb

Wizard