There are practical and psychological implications when on/off switches don't say what they mean, and don't mean what they say...
Bill Schweber, Site Editor
On most of today's electronic products, the front-panel on/off control is a processor-controlled soft function. It doesn't actually disconnect the power source from the electronics.
The reasons for this are well known: current is needed to keep some internal functions alive, even if quiescent, such as for that electronic wake-up; for a signal from an IR or RF remote control; or to keep the many subsystems in a car ready and primed. In other cases, it's simply cheaper, and more compatible with the packaging, to use a momentary contact button for the switch function rather than a tangible, mechanical, latching switch device.
The downside, of course, is the eternal drain. Auto vendors have strict limits on standby current allowed for each subsystem, but those trickle currents do add up to a respectable flow, and a car that hasn't run and thus recharged for a month can have a dead battery. My digital camera depletes its lithium-ion batteries in five to six weeks while "off", as another example; they are not cheap, and the uncertainty makes any spontaneous grab-and-go a risk . The inexpensive sonar-based "tape measure" I have drains its 9V battery down in just a few months (I have no idea what circuitry within the unit needs that continuous trickle, BTW). I finally beat that aggravation by opening the case and installing a tiny, $2 toggle switch, in series with the battery. This gave me a real sense of triumph and satisfaction: I met the enemy and defeated it, and at low cost!
Toggle switches, along with slide and rocker switches, make a definite, tangible, on/off statement. When it's off, there is no power drain, and your batteries and circuitry get a well-deserved rest. Even nicer, if you're in troubleshooting mode, you can poke at pick at the PCB, looking for loose connections, as well as study the internal construction, without danger of unintentionally short-circuiting those micro-spaced leads and components. It's the luxurious feeling of freedom.
I'm no fool; I know that soft switch functions and internally kept-alive circuits are the right thing in most designs, from both cost and functional requirement perspectivse. But in the analog world, where products are defined by their schematic and data sheet more than by system software, I still think about the implications of the difference between tangible versus virtual on-and-off. It's all about the function actually meaning what it says, and saying what it means. There's no ambiguity or "it depends" mindset, and I like that.