Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[SquatchHammer]

As for the thread. I couldn't find a thread here to ask people on how to work with circuits or just modify basic electrical devices.

I want to receive radio in my room with my new alarm clock radio and with the limp "antenna" (if you could call it that) cannot receive radio signals. My older one could and it did not have an external antenna. The only way I can think of is to either make a metal rod that the wire can be soldered onto or I have to do more than that. I would like to have this thread as sort of a discuss/ help me thread if it's possible.

[Bauglir]

What I know of how antennas work suggests that you will have no hope if you're not using the built-in antenna, or one built to its specs (which you almost certainly don't have), because the circuits that decode signals are designed for it. If taping it to a stick to straighten it out doesn't work, you will likely need to return it for a model that isn't faulty. However, I don't know much about these things, having started learning about them literally last week.

Also wtf is up with the thread name

[penguinofhonor]

.

[GiglameshDespair]

How did you spell electrocution wrong but electronic right?

[SquatchHammer]

What I know of how antennas work suggests that you will have no hope if you're not using the built-in antenna, or one built to its specs (which you almost certainly don't have), because the circuits that decode signals are designed for it. If taping it to a stick to straighten it out doesn't work, you will likely need to return it for a model that isn't faulty. However, I don't know much about these things, having started learning about them literally last week.

Also wtf is up with the thread name

I thought it was I needed [Tim voice] Moar power [/Tim voice]. I already tried taping the cord as high up to see if its a length issue.

How did you spell electrocution wrong but electronic right?

Also wtf is up with the thread name

Yeah, I thought this was a self-mutilation fetish thread. I am very disappointed.

In one of my jobs, I had to manufacture electronic components. It ment you could shock, burn, and get spinters of individual wires stuck in your fingers.

Rebellious fingers....

[penguinofhonor]

.

[Gunner-Chan]

I'm gonna admit, right up till reaching the last bit of the name I thought maybe this was a masochism topic or something. I am disappoint.

[GiglameshDespair]

I've had metal splinters from when I worked as a wire maker. One of the damn things was tiny, didn't come out for weeks. Irritating little thing.

Clearly there's demand for a machochism topic, though.

As for the thread. I couldn't find a thread here to ask people on how to work with circuits or just modify basic electrical devices.

I want to receive radio in my room with my new alarm clock radio and with the limp "antenna" (if you could call it that) cannot receive radio signals. My older one could and it did not have an external antenna. The only way I can think of is to either make a metal rod that the wire can be soldered onto or I have to do more than that. I would like to have this thread as sort of a discuss/ help me thread if it's possible.

You need to replace the antenna with one the same length, I would imagine.

[dragdeler]

I think this should go into the life advice section, but I am a sucker for necroposting and general discussion, so here goes nothing

It least it won't be my thread when this dies it's inevitable dead, like my rasberry clone thread did.





Here is the plan:
I want to build an ebike battery myself, I got a "smart bms", eventhough I do not know in detail how I will wire everything, just assume its a 48V ebike battery. So it should have between 48V and 54,6V depending on charge state. I have a stepdown module, to do a 12V circuit for music, lights etc. Now, I'm citing these details ahead because they might be pertinent, but let's go with the simplest stuff first, see if that gets any answers and build up from there.

So the step down does a 12V circuit, let's just assume I figured that out. For my leds: need I limit the current if I can provide the correct voltage? Can I reliably provide a stable enough 12V with my step down converter, or do I need to be concerned about my the motor causing huge ripples in the battery? Then there is thermal runaway... Best to put in a resistor just to be safe right? What kind of resistor, the ones with the color codes, or the glass cylinders with the metal edges, or like the flat metal clips in plastic (fuses?)

How to pick resistor size: (it says Resistor = (Battery Voltage – LED voltage) / desired LED current)
20w led -> 20w/12v=1,66a -> 12-12/1,66= 0/1,66 ... uhm yeah that's 0, do I not need a resistor?... ok let's assume "battery voltage" slightly higher so like 0,1/1,66=0,05999 -> I need a 0,6ohm resistor?
60w led -> 60w/12v=5a -> 12,1-12/5=0,02 -> I need a 0,02ohm resistor, is this correct ? Am I being dumb at math?

So the resistor would go somewhere along the red wire?

[Lidku]

dat necro tho

[McTraveller]

Wait, are you using pre-packaged LED "lightbulb replacements", or are you getting individual LEDs?

If it looks like a traditional lightbulb, just give it 12V and it will be fine.

If it's a "raw" LED, you need to know the voltage and current rating of the LED, specifically it's forward voltage and current.  The forward voltage of an LED is probably going to be like 3.6V, not 12V. I'd be surprised if the total current of a single LED is more than 100mA (0.1A).

So your resistor really needs to be something like (12-3.6)/0.1 = 84 ohms, probably need to pick a 120 for that.  But you'd need probably a 5-watt resistor for that, since I^2 R = (0.1^2) x 120 = 1.2W, which is going to explode a standard 1/4 or 1/2W resistor.

[dragdeler]

Is there a way to tell for how many watts a resistor found in the wild is rated? I understand about the colorcode but that ain't it or is it? Is it only by size/weight?


I got a led strip that can serve as brake light, turn signals, rear light and urgency orange flashing (how you call that again). It's rated at 6w but I don't know if that's 6w for all leds at once, or just one color, came from china without manual. It's like a quantum board basically, but flexible.


The others are motorcycle lights / truck working lights. Most comparable to flashlights with leds, except there is some stuff missing like there is no battery bay or switch obviously.






But also today was spent trying to learn what relays are and how they are used in motorcycles and cars. When I asked yesterday, in my head I was going to go from the step-down, straight into switch, then resistor maybe, then to led. But maybe it is better to use a motorcycle relay box and that solves all my problems, but maybe it is cheaper AND lighter, to just do it from single components and slap that on a piece of garbage plastic/wood I found or something like that.

Does anybody know how this type of connector is called?

[McTraveller]

Colorcode is resistor value and tolerance.  Otherwise it's size. Pretty sure an online search will help you.  Generally a resistor you find in the wild - the ones that are little cylinders about 1cm long - are 1/4 or 1/2 watt.  Higher wattages start having metal and fins attached.

That plug type is a "trailer wire extension plug" or something like that - standard for connecting a trailer's lights.

[dragdeler]

Ok so I got a lab power supply so I could be less of a fumbling monkey in the dark.

The two "flashlight" types led seem to be current limiting, they quickly reach max brightness where they simply will not accept any additional watts, as I raise the voltage, the amps drop. They seem idiot proof but they are nowhere near their rated wattage... Should I worry that they will loose they current limiting capacities when exceeding their rated wattage, or was that just chinese advertisment all along?

The led strip is way more complex, it accepts more watts as you raise the voltage, I was at twice the rated voltage, yielding like 3-4 times the rated wattage and amps still kept rising with the volts, I didn't dare to go look for a point where it would start limiting current that far outside of it's rated specs, eventho you probably cant trust specs posted on aliexpress.


So far so good, looks quite manageable.


But yesterday I wanted to try the whole thing through the step down module, one multimeter to measure amps and the other to measure volts and I couldn't figure it out... At no point was I outputting something. There is like a port for an on'off button I tried with a standard computer switch but still nothing... Also how am I supposed to spin those tiny screws to adjust the CV-CC values, without touching no exposed parts preferably heh... how can I tell it's not adjusted to awful specs before blowing a consumer? Very frustrating and inconclusive experiment. Also there is one capacitor that doesn't look well, couldn't tell if it was this way before I started messing with it or not.