Ask an Electrician anything...

[dundarach]

If I have 12v's DC from a Scalextric transformer, how can I step this down inside a model to 5v's DC in a simple component say 1cm without much heat.

So that I can use 5v motors rather than 12v motors, across the power band from the standard Scalextric controllers.

Hugs kisses and thanks

[phumy]

Whats the average Day Rate for a sparkie?

[eltawater]

What's the worst thing you've seen which has prompted you to declare "No f**king way am I touching that" ?

[Volare]

dundarach said:

If I have 12v's DC from a Scalextric transformer, how can I step this down inside a model to 5v's DC in a simple component say 1cm without much heat.

So that I can use 5v motors rather than 12v motors, across the power band from the standard Scalextric controllers.

Hugs kisses and thanks

You will want a voltage regulator using a '7805' IC.

[LostM135idriver]

Baldchap said:

ruggedscotty said:

Electricity - its a flow of molecular matter. dc it flows around a circuit. ac it vibrates in a circuit.

Isn't it the flow of electrons, i.e. subatomic particles?

Yes

[LostM135idriver]

What do you find most satisfying in your work?

[Countdown]

If you could start all over again would you still choose to be an electrician?

[toasty]

Do you smoke rollies?

[dundarach]

Volare said:

dundarach said:

If I have 12v's DC from a Scalextric transformer, how can I step this down inside a model to 5v's DC in a simple component say 1cm without much heat.

So that I can use 5v motors rather than 12v motors, across the power band from the standard Scalextric controllers.

Hugs kisses and thanks

You will want a voltage regulator using a '7805' IC.

Awesome

[Wheelbrace]

Do you know the difference between God and an electrician?

[steve-V8s]

A Sparky question rather than one about your van.

Can I, within the regs somehow mix PME and an earth stake ? The previous house had a nice big earth stake where the current one is PME. I have some equipment which is sensitive to supply noise and some which generates RF earth currents. The PME earth, where probably electrically safe has a far higher impedance at high frequencies and is less than ideal. With an earth stake system it was possible to whack in an additional stake local to the equipment and all was well.

Plainly with PME that would be unwise as my stake could end up being the earth for a fault in the neighbour's house and if I separate the two earths the chassis of my equipment could be at a different potential to other things nearby.

Why PME is now preferred is a mystery to me, I can perhaps see it for a block of flats but not for individual dwellings, presumably it is cheaper to install but I can't see any way it is actually better. There are now so many cheap plug in power supplies in use, all adding noise to the supply which you can't filter out without a good low impedance local earth.

[MK1RS Bruce]

How do you connect the cable between the consumer unit and the meter, there doesn't seem to be anyway to isolate the top of the meter to make such connections in mine.

[Countdown]

Wheelbrace said:

Do you know the difference between God and an electrician?

God doesn't think he's an electrician?

[Countdown]

How easy is it to bypass the meter?

Asking for a friend.....................

[biggiles]

dundarach said:

Volare said:

dundarach said:

If I have 12v's DC from a Scalextric transformer, how can I step this down inside a model to 5v's DC in a simple component say 1cm without much heat.

So that I can use 5v motors rather than 12v motors, across the power band from the standard Scalextric controllers.

Hugs kisses and thanks

You will want a voltage regulator using a '7805' IC.

Awesome

7805s can dump a lot of heat as they are a very simple design. If your Scalextric models can't handle this, then there are other options - 20 years ago I was using DC/DC switching regulators from Maxim which were almost as simple to use as 7805s. Hopefully the 7805 is sufficient.

ruggedscotty - how is a £200 Fluke multimeter better than my basic £30 sets? (For enthusiastic DIY use).

[brman]

steve-V8s said:

A Sparky question rather than one about your van.

Can I, within the regs somehow mix PME and an earth stake ? The previous house had a nice big earth stake where the current one is PME. I have some equipment which is sensitive to supply noise and some which generates RF earth currents. The PME earth, where probably electrically safe has a far higher impedance at high frequencies and is less than ideal. With an earth stake system it was possible to whack in an additional stake local to the equipment and all was well.

Plainly with PME that would be unwise as my stake could end up being the earth for a fault in the neighbour's house and if I separate the two earths the chassis of my equipment could be at a different potential to other things nearby.

Why PME is now preferred is a mystery to me, I can perhaps see it for a block of flats but not for individual dwellings, presumably it is cheaper to install but I can't see any way it is actually better. There are now so many cheap plug in power supplies in use, all adding noise to the supply which you can't filter out without a good low impedance local earth.

PME is cheaper to supply (less cabling) than TNS and generally lower impedance (at 50Hz) and safer than TT (earth spike). There is nothing stopping you converting to TT if needed. In fact this is quite common for outbuildings (eg garages) as exporting PME is not always a good idea.
a quick google found this which explains it: https://professional-electrician.com/technical/str...

edit: btw, I just re-read your question. You don't just whack an earth spike in parallel with a PME earth. You need to separate the two earthing systems. So yes, you want to do it for a building, not a single bit of kit. I am also curious what equipment you have that cannot filter the noise locally?

Edited by brman on Wednesday 27th October 09:42

Edited by brman on Wednesday 27th October 09:43

[brman]

biggiles said:

ruggedscotty - how is a £200 Fluke multimeter better than my basic £30 sets? (For enthusiastic DIY use).

If you mean for general electrical/electronic stuff then it isn't. I have an expensive wavetek meter and a cheap UNI-T. The UNI-T gets used 99% of the time as it has more functionality and is easier to use.

If you mean for an electrician then you really need a multifunction tester. A different beast altogether (and a lot more expensive than a fluke multimeter!).

[zetec]

Have you ever stuck your finger in a plug socket to make your hair stand on end?

[Volare]

biggiles said:

7805s can dump a lot of heat as they are a very simple design. If your Scalextric models can't handle this, then there are other options - 20 years ago I was using DC/DC switching regulators from Maxim which were almost as simple to use as 7805s. Hopefully the 7805 is sufficient.

ruggedscotty - how is a £200 Fluke multimeter better than my basic £30 sets? (For enthusiastic DIY use).

Yeah there are better options out there, but none small enough, it will be primitive if its going to have a 1cm footprint.

something like this?

https://www.unmannedtechshop.co.uk/product/micro-b...

Dont know how much current a scalextric car pulls.

[stressfree]

Hi, we bought a new build house and asked to install the outside socket. Socket is installed as a spur from the inside. My concern is that there is no isolating switch inside for the outside socket (water ingress or fault will be tripping an internal rcd on the same ring or someone can steal the electricity when we are not at home). Should they have installed the isolating switch or a separate rcd in the consumer unit? What is required by the regulations?

thank you