3 pronged electronics into a 2 prong continental adapter?

Protect it from what?? If you use a three prong plug into 2, it will work but it will not be grounded. Just get a three prong - they are cheap.

What small adapter?

If you are referring to the "continental" plug adapters sold by Rick, they are only suitable for 2 pronged devices (like phone chargers). If your laptop has 3 prongs, you should get a 3 pronged adapter. These are not sold by Rick, but you can get them from various other places, including Amazon and Magellan.

However, while the 2 pronged adapter will work all over the continent (except it will not fit in some Swiss outlets), there are variations in 3 prong outlets. So, tell us which countries you need to use your laptop in, and we can make sure you get the right one(s).

this small adapter

This? I think you forgot to include the link. But, no. If the device you want to want to use has a 3-pronged plug, a 2 prong adapter will not provide the protection the device with a three pronged plug was designed to have.

The third prong is a grounding pin. There are adapters available (although not a single one for every country) that will provide grounding protection.

This adapter will work in most places on the continent (except Switzerland and maybe Italy).

What countries are you planning to visit?

I got a grounded adapter at Radio Shack.

Sorry, I wasn't clear.... I did mean the 2 round prong adapter used on (most of) the continent, though I'm only going to France. I should have investigated further, didn't realize the outlets there can accommodate a 3 pronged device.

susmcquiggan, It would help if you provided a link to a picture, then we would now what you were talking about.
If your device (laptop charger) has 3 pins/prongs, the 3rd one is there for a reason. It is the earth (safety) connection, and if you do not connect it, then you risk getting fried if a fault develops.

didn't realize the outlets there can accommodate a 3 pronged device.

Yes, outlets in all European countries take 3 pin plugs, including an earth connection. In some countries the same outlets also take 2-pin plugs, for devices which do not need an earth connection, for example phone chargers. But, plugs and sockets are different in different countries, which is where it gets complicated.

• If you have a 2-pin appliance (which you don't), then a 2-pin "Europlug" (photo here) is what you need.
• If you have a 3-pin appliance, then it is different in different countries. A so-called "Schuko plug" (photo here) works in Germany, France and most other European countries.
• Switzerland and Italy have their own systems, For 3-pin, you need a Swiss or Italian plug respectively, but 2-pin Europlugs (if they are the correct shape, which some adapters are not) will fit in Swiss and Italian outlets.
• The UK has a totally different system, with 3 flat pins. It needs a totally different adapter.
• And, all countries in Europe are 220V AC 50 Hz. You need to check your appliance will accept that (read the small label on the laptop charger). If not, you will just fry and and be a fire hazard.

Clear?

If you have a 2-pin appliance ..., then a 2-pin "Europlug" (photo here)

It should be added that the Europlug works fine with US appliances that are double insulated (box in a box symbol; most computer power supply bricks) and have a non-polarized US plug (both blades the same width). However, most US appliances with a two blade plug are polarized (one blade wider). The wider blade has to be connected to a neutral conductor in the power system for safety. Most European power systems are not polarized, so the safety features can be lost.

Don't use a device with a polarized plug in Europe (except possibly Switzerland).

Note: Swiss systems, because the grounding pin hole is offset, can only be connected one way and the power is polarized. I have seen grounding (3-pin) adapters for Switzerland which had the blade slots properly polarized for a US polarized plug.

Lee, susmcquiggan, UK plugs (photo here) are also polarised. There is no 2-pin version of the UK plug, so appliances which do not need earths have to have a plastic 3rd pin. The black plug in the photo is an example. But, all appliances sold in Europe have to cope with non-polarised sockets (German Schuko plugs can be put in either way around), so no appliances rely on the polarity.
Since the same computer and phone powers supplies are used worldwide (they are all marked 110-230V AC), they have to be designed to work with either polarity. Only devices designed to work only in the US would rely on polarity, in which case they probably won't accept 220V AC.

Since the rules for plug adapters (bullet points in my last post) are simple, but they are misleadingly phrased on many websites.

OK, I should have said continental Europe. I guess since the Brexit vote, I don't consider the UK to be part of Europe. Their power, however, is polarized. A proper adapter would preserve the polarization for a polarized US device.

By the way, if the UK really does go out, will they go back to 240V. And will the continent go back to 220V.

Only devices designed to work only in the US would rely on polarity, in which case they probably won't accept 220V AC.

There are hair dryers, curling irons, straighteners here with 115V/230V switches but most have polarized plugs. I once bought one at a thrift store for a couple of dollars and took it apart. The only safety provided by polarization was that the single pole switch was on the "hot" line, so that, on a polarized power source, an internal short would not cause the device to turn on unexpectedly. If it were connected to a non-polarized power source, an internal short could cause it to come on unattended and start a fire.

Most computer power supplies today are double insulated with a non-polarized plug. My last laptop was a small netbook with a grounding (3 prong) plug. The one before it had a polarized plug.

I went to a luggage store today to sort out my needs for France, according to your suggestions:
I have 2 adapters that will work with my phone charger/camera battery charger and the voip telephone, and will purchase 2 of the grounded adapters, one each for my laptop and the vonage modem. This is the first time we've traveled to Europe with any type of electronics, so have made sure all 5 pieces have the built-in 110/220-volt converter.
Thanks all again so much!

The UK is effectively still on 240V and nearly all of the continent on 220V. The 'harmonisation' on 230V was achieved by altering the tolerances.

But the original intent was that the tolerances be progressively tightened over time until everyone is on 230V. You Brits were upset because your electric kettles would not heat up as quickly on the lower voltage. If you leave the EU, will you abandon the harmonization of voltage and stay at 240V? What about Ireland? Or the new Republic of Scotland, after they vote to leave the UK? (BTW, what will that be called. Scoxit is difficult to pronounce.) I think standardization on 230V is a really good idea.

Keith,

What is the official tolerance range for U.K. electrical utilities? It's very easy to provide a voltage at any level within a tolerance range by use of on-load tap changers installed in distribution lines close to the load point. We use that method here, especially on long rural distribution lines where the voltage levels can vary during the day depending on demand. If you're using the same method in the U.K., it should be relatively easy to set the optimum point at 230 VAC +/- (or any other desirable level).