Maker Pro
Maker Pro

Calculating values...

Gav2k

Apr 17, 2014
3
Joined
Apr 17, 2014
Messages
3
Hi,

Quick summery..

Basically a friend has a bmw x5 which has an issue with the stereo, bmw back in 2002 made a part to fix the issue but this part has since been discontinued and the replacement part only fits newer models.

The part looks to be a simple resistor and capacitor but obviously I need to values which bmw won't give out to be able to order the parts and solder them in.

The picture (hopefully attached to this post) shows the circuit and it's a car so let's assume 12-14.4v dc.

It has to come out as 12-14.4v but the bmw specialists do tell me the circuit is purely designed to cause a 5 or so second delay on powering up the systems amplifier.

Can any of you guys work out what values I need so I can pop into maplins.co.uk and pick the parts up.

Thank you in advance
 

Attachments

  • image.jpg
    image.jpg
    46.3 KB · Views: 123

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
Hello and welcome to Electronics Point :)

That diagram doesn't have component values for the resistor and the capacitor. There is one clue: the capacitor has a positive symbol on one side, which means it's probably at least 1 µF.

You could try a 470 µF capacitor and a 10k resistor. This combination has a "time constant" of 5 seconds, but this doesn't mean it will necessarily cause a delay of 5 seconds; that depends on the characteristics of the things on both sides of the circuit. It's likely the delay will be shorter than 5 seconds. In that case, you can try a higher resistor value. So you could buy some other values at the same time - 33k and 100k, for example.

Here are references to parts on the Maplin site:

Capacitor, electrolytic, 470 µF, 16V: http://www.maplin.co.uk/p/470f-16v-85c-radial-electrolytic-capacitor-vh46a
Resistor, 10k: http://www.maplin.co.uk/p/metal-film-06w-10k-ohm-resistor-m10k
Resistor, 33k: http://www.maplin.co.uk/p/metal-film-06w-33k-ohm-resistor-m33k
Resistor, 100k: http://www.maplin.co.uk/p/metal-film-06w-100k-ohm-resistor-m100k

Good luck :)

If you need any more info, just ask.
 

Gav2k

Apr 17, 2014
3
Joined
Apr 17, 2014
Messages
3
After looking into it more it's a 3-5 second delay so it seems to be correct. Are the parts directional?

Thanks so far

Gav
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
The capacitor is polarised. The polarity is marked on the side of the component. Also, the positive lead is longer than the negative lead. The resistor isn't polarised.
 
Top