It is common in folklore for evil or "unnatural" creatures to be unable to cross running water. For example, this is a traditional attribute of vampires: http://en.wikipedia.org/wiki/Vampire

Tolkien himself noted that this idea was difficult to sustain for the Ringwraiths. In particular, they would have had to cross the river Greyflood (which had no bridge or ferry) in order to travel from Mordor to the Shire. (I don't have the citation to hand, it may have been in Unfinished Tales.) He seems to have gone ahead with it anyway, in order to emphasise that the Ringwraiths were inhuman, undead creatures. 

Why are the ringwraiths fearful of coming in contact with water?
Few questions about a little Home-Automation project I am trying.

Below is the schematic which I found in an article, slightly modified to suit the parts I have in hand --

Original had,

Q1 = BC548
Relay = 12V coil voltage


Mine has,

Q1 = BC547B
Relay = 5v coil voltage


Q1) Is that an acceptable conversion ? 

Note: The BC547B has Vcbo:50V, Vceo:45V, Vebo:6V, where-as the BC548 in original circuit has Vcbo:30V, Vceo:30V, Vebo:5V, rest of the parameters being pretty same as per datasheet (hFE:220-450).

The relay is the SPDT PCB-mount kind (rated for 10A @230VAC), also called "sugar cube".



Q2) The load I am trying to drive is resistive (60W 220VAC incandescent lamp). What changes might I need if I would like to drive loads like --


Fluorescent lamp
Fan (220VAC, 60W)
1HP Water pump (220VAC, 800W) -- One thought is to use higher current rated (e.g. 30A) relay. But, I think I need to worry about EM feedback which might cause arcing and destroy the EM relay.


Q3) Right now I am making this on a veroboard (el-cheapo phenolic kinds). While I understand that this may be sufficient for the lamp/fan control, I am wondering if I need something better for higher loads, s.a. the Water-pump control ? What is the minimum gauge wire to be used for this purpose ? What kind of connectors (terminal blocks) could be used ?
