One extra thing that having separate warts for each devices gives us is isolation _between_ devices. If you connect 2 or more devices to a common universal P/S, you would run the risk of ground loops, and since many wart powered devices handle audio and/or video signals, this could be a problem. Any comments? I like the idea of voltage compatibility coded plugs, but it would be nice to come up with a solution that works for the thousands (millions?, billions?) of wart powered devices already in people's homes. Maybe too tall an order. Martin R. Green elimar@bigfoot.com PS. I have a couple of devices that are totally unregulated internally or externally, and can work on, say, 9-12V, but would fry on 15V+. ---------- From: John Payson[SMTP:supercat@MCS.NET] Sent: Thursday, September 04, 1997 5:05 PM To: PICLIST@mitvma.mit.edu Subject: Re: PIC power supply ... > Well, I've thought about that one before, but the problem I've always had > with the idea is that it would be too easy for even experienced users to > plug a 9V device into a 15V socket (you get the idea). Of course, this is > possible with warts too if they use the same plug and you get them mixed > up. Most of the devices I'm currently running from warts are not > internally regulated. But the current situation, 1 wart per device, is > ridiculous. While there are a few devices I've seen that rely on regulated wall-wart supplies, the vast majority do the regulation internal. I think it's 'cos the price difference between unregulated and regulated warts is higher than the price of a 7805 and two caps (plus, a device with a regulator on-board is less likely to go "boom" if connected to the wrong wart). A number of them also have a protection diode between the input and the regulator (cheap, but it means they'll run off just about anything). What I'd like to see would be a standard for plugs/sockets such that a plug would fit in any compatible socket. Probably a two-pin molex-style connector, polarized, and with notches or projections on the top and bottom to code for voltage, current, and AC/DC. A device which could accept anything from 9 to 15 volts AC or DC could have lots of notches in it, to fit a variety of plugs, while a device that needs +5 DC would just have one notch for +5 and one for DC (and one for its required current dose). How does that sound?