Circuits Building Questions-9V to 120V transformer…Capacitors…Resistors…Boards…?
I am trying to build a phone ringer circuit based on this web page:
http://www.techlib.com/electronics/telephone.html
It is the second project. In this project is a 9V to 120V Power Transformer. I am having trouble finding this. I am buying most of the parts from www.mouser.com so if it can be found there, great, but anywhere works.
Also, I am wondering how to pick some of the other parts. The capacitors, for instance, have a rating in the diagram like .033uf, but when I go to buy capacitors there is a lot more information needed. How do I figure out what part I need? Same with Resistors, all it has is 22Meg or 220ohm but not any of the other information. Any help would be appreciated.
Finally, I need to buy some sort of board to build this circuitry on. Any recommendations as to what to do use?
Thanks in advance.
I have one of these that was build by the guy who designed the circuit, and I have taken it apart. The transformer in the unit has the following info on it, does this help:
702 2 5 6
ALE PL 12-01a (or oia, o1a, 0ia)
3 4
It is a bog-standard power transformer. Unfortunately they don’t specify what VA rating to use so it’s a bit hit and miss. I think this Mouser part might work: 673-030-7329-0 but you might consider going on ebay and looking for a few cheap ones of different sizes.
Ratings for capacitors will be voltage and tolerance. Tolerance doesn’t matter too much in that circuit, so you can ignore that. None of the capacitors has more than 12V on it, so choose a voltage rating of 12V or higher. Electrolytic caps (the ones with the + terminal) come in 16V and 25V versions.
Resistors also have a tolerance, usually 5% or 1%. Again, it’s not critical in that circuit. They also have a power rating. Standard resistors are 0.25 watt carbon film or 0.6 watt metal film. Either type will do, except for the 2x 10 ohm resistors which should be at least 0.6 watt rated I think.
For board, I’d go for stripboard, aka. matrix board. Like this (can’t find it in Mouser)
http://www.maplin.co.uk/Module.aspx?ModuleNo=47480
You will probably have to cut the tracks in places. There is a special tool called a stripboard cutter, but you can also use a small drill bit.
"does this help"
No 
If you can tell us the size of it, it might.
May 8th, 2010 at 4:11 am
It is a bog-standard power transformer. Unfortunately they don’t specify what VA rating to use so it’s a bit hit and miss. I think this Mouser part might work: 673-030-7329-0 but you might consider going on ebay and looking for a few cheap ones of different sizes.
Ratings for capacitors will be voltage and tolerance. Tolerance doesn’t matter too much in that circuit, so you can ignore that. None of the capacitors has more than 12V on it, so choose a voltage rating of 12V or higher. Electrolytic caps (the ones with the + terminal) come in 16V and 25V versions.
Resistors also have a tolerance, usually 5% or 1%. Again, it’s not critical in that circuit. They also have a power rating. Standard resistors are 0.25 watt carbon film or 0.6 watt metal film. Either type will do, except for the 2x 10 ohm resistors which should be at least 0.6 watt rated I think.
For board, I’d go for stripboard, aka. matrix board. Like this (can’t find it in Mouser)
http://www.maplin.co.uk/Module.aspx?ModuleNo=47480
You will probably have to cut the tracks in places. There is a special tool called a stripboard cutter, but you can also use a small drill bit.
"does this help"
No
If you can tell us the size of it, it might.
References :
May 8th, 2010 at 4:31 am
Transformer : 9 volts 1 ampere or higher for secondary winding.
8 ohms resistor: 5 to 10 watts
All other resistors: 1/2 watt 5% error
1000 uf, 220 uf, 100 uf capacitors : use 25 volts or higher voltage.
0.22uf; 0.01 uf ; 0.033 uf capacotprs : use 50 volts or higher voltage.
NPN and PNP matching pair transistors : see this link
http://sound.westhost.com/project3a.htm
This is an AF amplifier circuit using matching pair transistors. If you want a small power pair,choose Q5 and Q6. High power,choose Q7 and Q8. Mount them with a heat sink.
You may buy a piece of board that has many small holes to build this circuit. Some board has printed copper traces for universal project.
References :