Electronics Question (Relays)

[Pyrii]

While I passed my GCSE electronics, I got an E for not paying too much attention, so forgive the n00biness. I'm planning a project which I found the plans online for to mod my DTT3500 unit, and int he plans there's a 12v DPDT relay. But there's also a resistor that needs to be calculated apparently (Not sure why as there's a transformer which should provide consistent DC current inthe DTT3500.

The calculation requires knowing either "I RELAY" or "R RELAY" and I have no idea what either of these are, I've found out everything there is to know about relays and still have no clue what these refer to x.x

R1 = R RELAY / 4 or 15V / I RELAY

Help apreciated. Sorry of the n00bness of the question

[donkiddik]

Think that the "R" relay and the "I" relay refers to the resistance "R", or the current of the relay "I". Basic ohms law, resistance (r) = voltage (v)/current (i). looking at your calculation I think it means that the resistance or R1 is the resistance of the relay divided by 4, OR 15 divided by the current taken by the relay. Without seeing the circuit that's the only advice I can offer.

[Pyrii]

Creative DTT3500 Modification - Outbreak Labs

That's the project. Thanks for the refresher, I guess I really have forgotten most of GCSE electronics at that's fairly basic stuff. Anyways, From what I can tell, the omron G5V-2-DC12(pdf-link) has a coil resistance of 288ohms, I'm not sure if the RATED current is what it actually draws from the current passing through. Thought they do state power consumption as 500mW (or 0.5W).

So long story short, 72ohms.

Now to find a supplier, or suppliers. Rapid Electronics aren't bad but I can't find cuttable breadboard.

[Agent]

The DTT3500 doesn't have a sub-in? !
I never noticed that on mine (have always done it via the creative DIN thing)

I swear the DTT3500 is the best system that Creative have made

[Pyrii]

Yeah, but the X-Fi series doesn't have a digital 4 pole plug for DIN, And Auzentech X-Fi Prelude + Xtender is about £180

So thinking forward a little. That and it just seems like something worth adding anyways. I also have my eyes on a new soldering iron anyways, as my current one's a mess =P And I want a finer tip for it too. And a desoldering pump (So I can fix the scart plug on the back of my crappy old TV)

[GAteKeeper]

Dont bother with the pump get desoldering braid, much better at attually removing the damn stuff.

Cant beat a proper home cinema amp and speakers though!

GK

[donkiddik]

Creative DTT3500 Modification - Outbreak Labs

That's the project. Thanks for the refresher, I guess I really have forgotten most of GCSE electronics at that's fairly basic stuff. Anyways, From what I can tell, the omron G5V-2-DC12(pdf-link) has a coil resistance of 288ohms, I'm not sure if the RATED current is what it actually draws from the current passing through. Thought they do state power consumption as 500mW (or 0.5W).

So long story short, 72ohms.

Now to find a supplier, or suppliers. Rapid Electronics aren't bad but I can't find cuttable breadboard.

I would get an 82 or 100 ohm resistor as they are the next highest value, you should be alright with the .5 watt version or if in doubt go for the 1w. Also have you checked Maplins as they stock electronic components ?

[Steve B]

Dont bother with the pump get desoldering braid, much better at attually removing the damn stuff.

Cant beat a proper home cinema amp and speakers though!

GK

Yep, its called Soldamop in maplin and its awesome stuff
The pumps really take practice, but this stuff is easy.
You need a half decent soldering iron though.

[Pyrii]

Maplins seem to be overpriced every time I go in there, and they always find some way of ripping me off, like when I returned something and brough something else, they didn't apply any of my discounts till after they'd done the refund, so I lost out of £5 of discounts.

BUt I suppose it's worth checking out for stuff I can't get at rapid, because rapid ARE cheaper.

Maplin > 480 Piece E3 Resistor Starter Pack
Rapid Electronics -