Soldato
Ahh right, should be ok then voltage wise. The Nixie clock instructions say the power supply must be at least 250 mA. My Netgear 12v adaptor is 135mA. Will this be ok?
***Official Electronics Thread of Officialness (it starts off with lots of Nixie Tube Clock goodness
- Thread starter Aod
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Ahh right, should be ok then voltage wise. The Nixie clock instructions say the power supply must be at least 250 mA. My Netgear 12v adaptor is 135mA. Will this be ok?
No it hasn't got enough current capability. I've got/had several Netgeat power supplies and I've never come across a 135mA one. Is that 135mA on the 12V DC or on the AC supply?
If on the DC output you can easily pick up 12v @ 1000mA (sold as 1A) which will be ample for your needs. I've bought a few to replace old Netgear power supplies (12v@1A) myself.
Soldato
Soldato
Two questions, looking for some advice on switches.
Looking for two things (both switches)
1: a toggle switch which has multiple options rather than your traditional in off. E.g. Different resistors on each switch.
2: some kind of rotational, dimmer switch kind of thing, that isn't huge and has lowering increasing resistance as you rotate...
Hope that makes sense, figured people in here would be best to advise.
kd
Looking for two things (both switches)
1: a toggle switch which has multiple options rather than your traditional in off. E.g. Different resistors on each switch.
2: some kind of rotational, dimmer switch kind of thing, that isn't huge and has lowering increasing resistance as you rotate...
Hope that makes sense, figured people in here would be best to advise.
kd
multipole switch wired to different resistors?
potentiometer.
available in huge range of resistances and form factors.
Soldato
Whats the potentiometer for? Most are rated to very low loads, typically a couple of hundred milliamps.
Soldato
Home made fan controller xD
So would need it up to about 12V
multipole switch wired to different resistors?
potentiometer.
available in huge range of resistances and form factors.
Thanks, I didn't think it would be uncommon, just a pain to find if I didn't know the technical name
kd
Here is the Adaptor. It appears to show 135mA AC & 1A DC. Does that mean it'll be ok?
Yes that's exactly like the ones I have. As I thought the 135mA is the current draw from the mains supply (AC) and not the actual DC power you get at the accessory plug.
1 Ampere will be plenty then.
These do show 18v or so unloaded but should settle down to 12v soon enough. I've never measured load voltage on these though but have used them for several different 12v needs.
KD - Potentiometers aren't really suitable for fan controllers as they don't have enough current handling. I've had a quick look at some potentiometers on the same place as you got those luscious pink LEDs from and they are rated as 0.2W which isn't enough for a fan really.
Rheostats are more suitable for fans but I could never find a good source.
What you'll need to do is create a simple circuit around a potentiometer, a transistor and maybe a capacitor or two to smooth things out. Or maybe a LM317T based regulator circuit using the aforementioned regulator and a potentiomter (here you'll drop around 2v so will get fan voltage up to a max of 10v).
Rheostats are more suitable for fans but I could never find a good source.
What you'll need to do is create a simple circuit around a potentiometer, a transistor and maybe a capacitor or two to smooth things out. Or maybe a LM317T based regulator circuit using the aforementioned regulator and a potentiomter (here you'll drop around 2v so will get fan voltage up to a max of 10v).
Soldato
Hmm, interesting that it's such a challenge, as clearly some fan controllers have the system in place. Figured it'd be nowhere near as complex if they can do it, but guess they have a much wider range of suppliers...
kd
Don't get me wrong. Loads of fan controllers use potentiometers but they will always have other components on board to sink the current from the fan itself. Rheostats are expensive. It's much cheaper to have a 20p potentiometer and a 5p transistor to do the job with maybe a resistor and a capacitor or two to add to the mix.
A fan controller was one of those projects I fancied having a go at but never got around to doing. I'm still using a rubbish £5 fan controller which has two faulty knobs. I did make a PWM circuit using a 555 timer IC and some other bits and bobs that controlled a 3 pin fan but never used it.
I'm not sure if this is correct but I just searched for Rheostats and the prices are £20+ for a single unit. Wow.
Take for example this Lamptron fan controller. You can see the components on the PCB. They consist of a TIP-110 component (probably a Mosfet), a capacitor and possibly an inductor while a potentiometer adjusts the fan for each circuit.
A fan controller was one of those projects I fancied having a go at but never got around to doing. I'm still using a rubbish £5 fan controller which has two faulty knobs. I did make a PWM circuit using a 555 timer IC and some other bits and bobs that controlled a 3 pin fan but never used it.
I'm not sure if this is correct but I just searched for Rheostats and the prices are £20+ for a single unit. Wow.
Take for example this Lamptron fan controller. You can see the components on the PCB. They consist of a TIP-110 component (probably a Mosfet), a capacitor and possibly an inductor while a potentiometer adjusts the fan for each circuit.
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Soldato
Yeah, they are pricey due to not just needing a carbon track to control the resistance. Usually wirewound to sink more current away! I have a PWM circuit kicking about based around a 555 timer which I used to control Dew Bands (Which I also made out of nichrome wire!) for my telescope. Made a twin channel 4 output one, worked very well.
Soldato
Soldato
Did anything happen with this?
Soldato
Well i've just been looking at CMOY parts on Farnell, and it's a LOT more confusing than i remember. There's stuff like quality capacitor manufacturers to look out for, having far too much choice, them "hiding" the part where it says it's a US part and it costs £15 to ship a tiny resistor the size of my little fingernail... then i look and realize half my basked has this. I raged. It's too late for this sort of thing anyway
Associate
A questions for you guru's!
1) I want to run this electromagnet (http://www.electriclock.net/acatalog/info_ELS_10003_R.html), am I right in thinking a constant 0.5A from a standard 9v battery would keep the magnet "on"?
2) How do I work out how long a battery will last?
3) What would be the easiest/cheapest way to have a button, which when pressed would trigger a random time period (between 1 and 4 seconds) to wait before dropping the current and thus turning the magnet "off"?
Many thanks in advance for any help
1) I want to run this electromagnet (http://www.electriclock.net/acatalog/info_ELS_10003_R.html), am I right in thinking a constant 0.5A from a standard 9v battery would keep the magnet "on"?
2) How do I work out how long a battery will last?
3) What would be the easiest/cheapest way to have a button, which when pressed would trigger a random time period (between 1 and 4 seconds) to wait before dropping the current and thus turning the magnet "off"?
Many thanks in advance for any help