"ccts" is a short form for "circuits". I use to recomend for begginers to imagine a sort of association between electrical and hydraulical systems: - tension could be the height of a water container to the "ground", or relative pressure (relative to ground, also, if you like); - current could be the water flow rate in time; - resistance coud be some kind of restriction in a pipe (and the pipe is a wire); So, in the first circuit one could say that you picked up a pipe out of the "10V" tank to the first restriction, anoter pipe to the second and then left open to the ground, so there is a water flow depending on those restrictions; the lower those restrictions, the higher the flow rate. You will also get pressure losses after restrictions and also along pipes, because pipes are restrictions themselves, so do wires in electricity, because there is no material (in normal conditions) that has no resistance at all. If you want to drive a load that has a different power supply than the PIC or may drain more current than a PIC pin may deliver, you have to build an interface that can be as simple as a transistor: the PIC pin should be connected to the base terminal of a transistor through a resistor (for current limiting), the emiter to the ground and the colector to the negative pin of the load (your laser) and its positive to the power supply. Let me try to draw it: +6V --- DIODE | |\ | |----------| >|------------- | |/ | | | + | LASER | | - | | | C \ | ----------- \| B | VCC | |----- R (10k) ----| PIC | /| | | E / | | | | ----------- | ----- --- - As there is just a little difference in the supply voltages for the laser and for the PIC (just 1V) you may use a diode as shown (I think) above: the voltage drop in a normal diode is something like 0.6 to 0.7V, and the PIC will work with something between 4.5 to 5.5V (if you want, you may add another diode in series, just to be safe). The transistor may be any general use NPN, or, if you like, a 2N2222 or a BC337. You will have to look for the specs of the laser to make sure about the voltage levels in which it works fine. Hope this helps Francisco Kieren Johnstone wrote: >Yay! ^_^ You must excuse me, I think I'm on a sugar high. >Okies, just thought of another question (after the natural "what's a cct").. >If I wanted to use a 5V PIC that uses < 0.6mA typically to switch on/off a >6V, 30mA laser module (I like lasers they're pretty), well.. how would I do >it? :) Obivously I'd need a 6V (or more) source, no? Would I then use a >voltage divider on one end to drive the PIC.. the laser would run off the >other parallel-ly connected circuit, but how would an outpin pin from the >PIC switch it? I'm thinking "relay" but also "maybe that's a bit bulky". A >transistor? How would I connect it? :) > >-Kieren > > >----- Original Message ----- >Wrom: CONEUQZAAFXISHJEXXIMQZUIVOTQNQEMSFDULH >To: >Sent: Thursday, July 11, 2002 8:20 PM >Subject: Re: [EE] Will the questions never end?! ;) (small attachment) > > > > >>-----BEGIN PGP SIGNED MESSAGE----- >>Hash: SHA1 >> >>Yes. It would be 10V That's what parrallel ccts are all about. >> >>- --Brendan >> >> >> >> >>>Hi, >>> >>>I've been studying my introductory textbooks for a while now, >>>getting this one theory right would be a milestone for me. I've >>>attached a .gif of the question in question :D. Basically, if I >>>have two circuits, connected in parallel to a source (lets say a >>>10V battery), and voltage-divide on one of them with resistors, can >>>I create 2 off-coming voltages of (lets say for example) 4V and >>>6V... and then, could I still get a 10V supply from the other >>>connected circuit (same source), and divide that as I saw fit? :) >>>If this is true, am I to assume that in general, people use 2 >>>small, different value resistors in series, and run a load in >>>parallel with one of them to lower voltages? :D >>> >>> >>-----BEGIN PGP SIGNATURE----- >>Version: PGPfreeware 6.5.8 for non-commercial use >> >>iQA/AwUBPS3alwVk8xtQuK+BEQJqjACg9HUr94nln+uGm0uCDezb/9OUTdcAoPp9 >>dn6/ApYp1R3IgaF7tcX66B46 >>=IwKr >>-----END PGP SIGNATURE----- >> >>-- >>http://www.piclist.com hint: PICList Posts must start with ONE topic: >>[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads >> >> >> >> >> > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads