How to use an Android phone or tablet to make a projector presentation?

I have planned for some time to use a smartphone or tablet to give scientific presentations via projector, instead of using a laptop. I'm now thinking about buying a new Android smartphone, if I can be sure that in the end I'll be able to realize this goal with it. So my main question is: **What do I have to look out for in order to get a device with which I can give projector presentations?** I apologize that this question is not exactly about a concrete problem I'm faced with right now – I just don't want to purchase a costly device only to find out later that I can't do with it what I want. I therefore did some thinking and research about the *possible* problems, and ask you for advice on how to avoid a concrete problem to occur in the first place. Here are some issues that occurred to me: 1. In my experience most projector installations in lecture halls still only provide access to a **VGA** connector. I know that VGA as an analog signal requires D-A conversion from a digital signal, but I'm confused about how much effort this takes: [Some](http://www.amazon.de/gp/product/B004B65KXQ/ref=ox_sc_sfl_title_9?ie=UTF8&psc=1&smid=A2SPS3CI7RTX03) converters have the shape of a box which needs an extra power supply, [others](http://www.amazon.de/Adapter-Audio-%C3%9Cbertragung-Konverterkabel-Unterst%C3%BCtzung-digital/dp/B00DP1OOSK/ref=lh_ni_t?ie=UTF8&psc=1&smid=AEB9F56C3A3O6) are very small and don't need extra power. **What is the difference between these different types of devices, and which kind do I need?** Please note that the links are only meant as examples, I'm not asking specifically about these products. 2. Again in my experience, most installed projectors do not yet support Full HD, but still need signals at resolutions like 800x600 or 1024x768. At least [some](http://www.amazon.de/gp/product/B0085B5KPQ/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A2XW1R8G26C2W1) HDMI-to-VGA converters appear to support **downscaling** from Full HD to VGA resolutions. Since I probably can't control this from the smartphone/tablet: How does it work? Can I trust that the optimal resolution is automatically negotiated between the adapter and the projector? Can I expect a decent-looking result from the downscaling, or will it be all washed out? Practically speaking: **Is there a specifically named feature of such converters that I should look out for when choosing one?** Again, the link is only for reference. 3. Android apps normally have screen output optimized for the fixed, physically small screen built into the device and not the flexibility that is provided by changing the screen resolution or resizing a window on a Desktop OS. Is it a realistic goal to achieve a **good presentation experience** from a mobile device similar to the one from a laptop? E.g. it appears not to be possible to get Adobe Reader for Android into a proper one-page-fullscreen mode. **Is there presentation software that does this better?** I'm mainly thinking of presentations in pdf format. And maybe there are caveats I'm not even thinking of?