Maximum VAC and Amp on breadboard? - Page 1
Forum section: electronics / projects

author: Mitchell Andrews
author_rank: Contributor
timestamp: December 13, 2013, 08:35:41 am
content: I have several small electronics breadboards. And I need to test some components using a 120 VAC. Can I have some advice about powering my boards using a 120 VAC power source. Can the boards handle this amount of voltage? And how much Current?

author: Electr0nicus
author_rank: Regular Contributor
timestamp: December 13, 2013, 09:50:23 am
content: I don't know exactly what you mean with "Archer" but if it's a standard breadboard, the voltages and currents you want to use are really problematic. 120VAC is really much for a breadbord, although thats not so a big problem as the 15A of current. As the component leads only sticked into some metal clamps the contact resistance is pretty high, (not comparable to a proper PCB). Therefore you get relatively high voltage drops and the metal clamps in the breadboard will very likely get pretty hot.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: December 13, 2013, 09:52:37 am
content: If you have to ask, you shouldn't be playing with mains at all...

author: Electr0nicus
author_rank: Regular Contributor
timestamp: December 13, 2013, 09:56:57 am
content: If it is a small circuit, you can try to solder it together with proper cables. But then you really have to know what you're doing and have to take te proper precautions and must obey the 5 rules every electician knows.

author: hans
author_rank: Super Contributor
timestamp: December 13, 2013, 10:04:37 am
content: Mains on a breadboardI exclusively use breadboards for low voltage (<30V) and low power (<1A) stuff. Anything above, solder the connections solid on a piece of stripboard. You don't want some piece of high power electronics to suddenly go crazy, open or short circuit or some weird crap because of a doubtful connection.If you deal with mains @ stripboard, you better remove the copper islands between line and neutral to increase isolation distances. because you know.. copper conducts electricity and stuff.But as said, if you have to ask..

author: Joule Thief
author_rank: Regular Contributor
timestamp: December 13, 2013, 10:14:52 am
content: I would add the largest gauge wire you may insert into a breadboard is usually 20 - 22 AWG.Safety concerns aside, the current thru the project will be severely limited by the gauge of the interconnecting hookup wire.

author: peter.mitchell
author_rank: Super Contributor
timestamp: December 13, 2013, 11:41:29 am
content: I suggest "old style" breadboarding, ie, grabbing an actual old wooden breadboard and hammering in some nails and wrapping your wires around them ect.

author: abbotsmike
author_rank: Contributor
timestamp: December 13, 2013, 12:02:36 pm
content: I feel the 15A may have been taken out of context here. Do you actually intend to use 15A in your circuit or is your supply actually just a mains plug? Either way, I wouldn't be comfortable running 15A OR 120VAC on a breadboard. I probably also wouldn't want to use veroboard. Look up the IPC specs for clearane and creepage, that should give you an idea of what is appropriate.Personally, If I wanted to prototype a circuit at those currents and voltages, I'd probably just work on an insulated mat (or block of MDF), screw or glue components down and point-point wire everything. It does have inherent safety risks, but it's how I've done high power circuits in the past.

author: akis
author_rank: Frequent Contributor
timestamp: December 13, 2013, 12:08:11 pm
content: Typical breadboard contacts are little metal clamps which make contact on two tiny points on the component leads. I believe anything over 100mA becomes problematic as you will be getting voltage drops in places where you would not expect. And the 120V is too much for a breadboard, something comes lose or makes contact and it's fireworks.

author: dannyf
author_rank: Super Contributor
timestamp: December 13, 2013, 01:16:25 pm
content: QuoteOn a specially-made board, yes if it is designed to handle that kind of power source.On a regular board, it is a sure way to get someone electrocuted and start a fire.

author: Mitchell Andrews
author_rank: Contributor
timestamp: December 14, 2013, 02:07:18 am
content: Thank you for your inputs.. I have a 110vac power strip with individual on/off switches for each receptacle. I'm simply adding a red LED power indicator (pilot light) for each one. The led is rated 120 vac 9 watts. My question about the breadboard specs, is because I am testing different types of diodes to use with the LEDs. I'm watching for temperature increase and reliability mainly. The breadboard would be nice for testing different Diodes. At this point I am getting fair results using 1N34A Germanium Diodes.

author: N2IXK
author_rank: Frequent Contributor
timestamp: December 14, 2013, 03:40:58 am
content: 9 Watts apiece for simple pilot lights? Why waste all that power? A few 9 watt class LEDs can light a room....Why not 120VAC neon panel lamps rather than LEDs? They use a lot less power, don't need inverse voltage clamping and transient protection, just a simple series resistor.

author: calexanian
author_rank: Super Contributor
timestamp: December 14, 2013, 03:49:45 am
content: I think your 1N34's are not gona last long. Some neons would be ideal.

author: IanB
author_rank: Super Contributor
timestamp: December 14, 2013, 03:52:13 am
content: Quote from: Mitchell Andrews on December 14, 2013, 02:07:18 amHoly Moly! 9 watts is area lighting, not a pilot light. What on Earth?Beyond that, I'm confused by the diodes. What are they for and why might they get hot? And a 1N34A? This diode has no purposes connected with mains voltages!

author: IanB
author_rank: Super Contributor
timestamp: December 14, 2013, 03:53:02 am
content: Oh, I get it. You are making the 1N34's light up and using those as your LEDs...

author: AG6QR
author_rank: Frequent Contributor
timestamp: December 14, 2013, 04:02:16 am
content: Quote from: Mitchell Andrews on December 14, 2013, 02:07:18 amAt 120V, 9W is around 75mA. That's a lot different than 15A. 75 mA ought to be tolerable. If you can use a fuse to limit the current to something in the neighborhood of a hundred mA or so, that would add a bit of safety. I wouldn't use any two adjacent rows of the breadboard, in order to keep some distance between voltages. More importantly, I wouldn't put any hands anywhere near the breadboard while power was applied.EDIT: but for a LED pilot light, you should be talking about something in the neighborhood of 20mA max, with a few tens of milliwatts.Quote from: Mitchell Andrews on December 14, 2013, 02:07:18 amThose diodes, according to the data sheet I found on the web, have a peak inverse voltage rating of 60V. 120V RMS translates to a peak voltage of about 170V, before we've allowed for any voltage spikes, surges, powerline noise, etc.It may work for a while on the breadboard, but you have no guarantees the diodes won't let the magic smoke go out one of these days when they are faced with too much reverse voltage. It's best to design according to the data sheet, and just use the breadboard to verify things after you've gone over the data sheet.

author: N2IXK
author_rank: Frequent Contributor
timestamp: December 14, 2013, 04:32:12 am
content: Why would you even consider the use of 1N34s for an application like this? They can't handle high voltages, and they are getting hard to find and expensive. 1N4007s, OTOH are dirt cheap and will handle 120V mains power without breaking a sweat.Save the germanium stuff for suitable applications, like RF detectors, balanced modulators, or other places where the lower Vf is needed.Still think you need to ditch the LEDs altogether, and go with neon lamps...

author: IanB
author_rank: Super Contributor
timestamp: December 14, 2013, 04:34:14 am
content: I think this thread is a troll...the only thing wrong is that the date is not April 1st...

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 14, 2013, 05:34:19 am
content: I have used "mains" on breadboards, but always through a small isolation transformer. I have even used voltages as high as a few kV (though very low current), just have to be aware of distance and reinforce insulation underneath with tape. Current is more problematic in that a few amps is a lot.

author: Mitchell Andrews
author_rank: Contributor
timestamp: December 14, 2013, 06:22:11 am
content: Quote from: calexanian on December 14, 2013, 03:49:45 amI agree with both of your conclusions.

author: codeboy2k
author_rank: Super Contributor
timestamp: December 14, 2013, 07:06:29 am
content: Whenever I breadboard mains powered stuff I stay away from the typical white strip breadboard... that's only for low-voltage, low current, < 30V or so, < 500mA or so.When I make up mains powered projects, I use copper clad board as a base, and wire it up Manhattan style, punching out circle rings for standoffs and can stack them two or three high if I need more clearance. I earth ground the main board, everything else floats above it and is point to point wired.I've used this style for prototyping offline switchmode PSU's with DC busses up to 400V no problem. Just make sure to maintain clearance and creapage distances appropriate for the voltages at hand.When I was younger and wired up 10KV filters and matching networks, I built it with 1.25" x 3" tall ceramic insulator standoffs screwed onto aluminum plate as a base, sliver plated copper tubing for point to point wiring, and just maintained proper spacing for the wiring, caps, inductors, etc, which were also mounted on ceramic standoffs. Everything was spaced well enough apart that there was no flashover. I actually learned this HV way first, and brought that style down to my lower-voltage work (120V, 400V, 600V)

author: Mitchell Andrews
author_rank: Contributor
timestamp: December 14, 2013, 07:40:21 am
content: Thank you codeboy2k!!!!!! You have an awesome solution that's truly related to this thread. Sounds like a great way to work out projects using Alternating Current at higher voltages. An upscale breadboard, properly grounded!

author: Bored@Work
author_rank: Super Contributor
timestamp: December 14, 2013, 08:13:52 am
content: Quote from: IanB on December 14, 2013, 04:34:14 amYep, the only thing missing is the phrase "and I want to control it with an Arduino".

author: oldway
author_rank: Super Contributor
timestamp: December 14, 2013, 08:25:18 am
content: I am making my own experimental single sided boards (130 x 180).No problem at all with 240Vac and 5A.

author: Ton
author_rank: Regular Contributor
timestamp: December 14, 2013, 05:25:18 pm
content: Even though some show a bit of contempt for data sheets in this tread, I dare you all with one from an actual breadboard compagny.http://www.busboard.us/pdfs/BPS-MAR-BB830+BB830T-001.pdfaccording to this data sheet the Max voltage is 36V and Max current is 2Aso probably not a good nor safe thing to apply 120VACjust my 0.02 bit coins

author: Zero999
author_rank: Super Contributor
timestamp: December 14, 2013, 10:46:16 pm
content: Quote from: N2IXK on December 14, 2013, 04:32:12 amWe've not seen the schematice. He could be using it in reverse parallel with an LED.

author: N2IXK
author_rank: Frequent Contributor
timestamp: December 14, 2013, 11:54:46 pm
content: Quote from: Hero999 on December 14, 2013, 10:46:16 pmI kind of figured that, but why spec a Ge RF detector diode for such an application? Certainly the 0.6V forward drop of a standard cheap Si diode is low enough to prevent reverse breakdown of a red LED. No need to go for the lower drop of a Ge.And, of course, no need to worry about any of that if neon lamps were used.....