How do I know which type to use ?

[geiristudio]

Hi,

I've been reading a lot about everything related to making pedals from scratch and I'm getting the gist of it but there's one thing I can't figure out. It's probably a very silly question but I need it answered.

I'm going to build this:



Okay, there are some resistors and stuff. I started to look around on banzaimusic to order the parts but then I got these options: http://www.banzaimusic.com/Resistors/.

How do I know from this type of schematic which type of resistors to use ? I know the complicated schematics show which type to use. I will learn by time to read them properly.

One last thing, what's the "E B C" going down in the bottom middle ?

[mysticwhiskey]

As long as you've got the resistor values correct, the only other relevant parameter is power rating (watts). That circuit probably requires only 0.25W resistors. You can go higher in wattage, but usually above 0.5 or 0.6W the resistors are physically larger so there may be some difficulties fitting them into the layout. For most of my builds I tend to use 0.6W metal film resistors, that's mostly what's available locally.

The EBC thing is marked as Q1, and is an NPN BJT transistor. This has three pins: E = emitter, B = base and C = collector. The orientation of this is important, put it backwards and the circuit won't function as designed. Other things to note: there's a couple of electrolytic capcitors in that circuit which are polarized, so they need to be inserted in the correct orientation.

[mictester]

As long as you've got the resistor values correct, the only other relevant parameter is power rating (watts). That circuit probably requires only 0.25W resistors. You can go higher in wattage, but usually above 0.5 or 0.6W the resistors are physically larger so there may be some difficulties fitting them into the layout. For most of my builds I tend to use 0.6W metal film resistors, that's mostly what's available locally.

The EBC thing is marked as Q1, and is an NPN BJT transistor. This has three pins: E = emitter, B = base and C = collector. The orientation of this is important, put it backwards and the circuit won't function as designed. Other things to note: there's a couple of electrolytic capacitors in that circuit which are polarized, so they need to be inserted in the correct orientation.

That's exactly right.

You also need to put the diodes in the right way 'round - that's one in each direction.

[roseblood11]

Resistors (and shipping cost) are much cheaper here:
http://www.musikding.de/index.php/cat/c ... -0-6W.html

btw:you don´t have to use the 1n270 - any other germanium diode will give the same sound. Use a cheaper 1n34a...
In many Lovepedals, there´s a combination of one Si (1n914) and a schottky (bat46), this could sound good here as well.

pinout of the 2n5088:
http://www.musikding.de/product_info.ph ... N5088.html

[geiristudio]

As long as you've got the resistor values correct, the only other relevant parameter is power rating (watts). That circuit probably requires only 0.25W resistors. You can go higher in wattage, but usually above 0.5 or 0.6W the resistors are physically larger so there may be some difficulties fitting them into the layout. For most of my builds I tend to use 0.6W metal film resistors, that's mostly what's available locally.

The EBC thing is marked as Q1, and is an NPN BJT transistor. This has three pins: E = emitter, B = base and C = collector. The orientation of this is important, put it backwards and the circuit won't function as designed. Other things to note: there's a couple of electrolytic capcitors in that circuit which are polarized, so they need to be inserted in the correct orientation.

So the watts don't matter that much ? I mean, if I'm making a pedal and I use 0.25W in one model and then make another exactly the same but use then 0.5W, would there be a big difference ? I'm guessing it should draw more power, right ?

About the other parts, like capacitors. If I got the values right, then I doesn't matter what type it is (unless stated in the schematics) ?

I just wanna make sure I've got this info right.

Thanks guys!

[deltafred]

So the watts don't matter that much ? I mean, if I'm making a pedal and I use 0.25W in one model and then make another exactly the same but use then 0.5W, would there be a big difference ? I'm guessing it should draw more power, right ?

About the other parts, like capacitors. If I got the values right, then I doesn't matter what type it is (unless stated in the schematics) ?

I just wanna make sure I've got this info right.

Thanks guys!

No, .25W is the power it will safely dissipate, the power it takes is determined by it's resistance and the voltage across it (or current through it)

Power = volts squared / resistance

or Power = amps squared * R

Most of the time the capacitor type does not matter too much (much debate on this point) electrolytics can be an exception though. As you say if it says a certain type in the schematic then best use that unless you know what you are doing.

Hope this helps

[deltafred]

The maths behind my previous post

Power is defined as Power = Amp * Volts

Ohms Law states that the current through a resistor (in amps) is equal to the voltage across it divided by the resistance (in ohms) -

Amps = Volts / Resistance

manipulating this we get

Volts = Amps * Resistance

Substituting this in the power formula gives

Power = Amps * Amps * Resistance = Amps squared * Resistance

or Power = Volts * Volts / Resistance = Volts squared / Resistance

If we have a 1k resistor with 5 volts across it then the power dissipated will be 5 * 5 / 1000 = 0.025W

The current through it will be 5 / 1000 = .005A or 5mA (this is true for DC circuits and some AC ones but not all and now is not the time to start explaining it as it would only confuse the issue).

So all that boring formula manipulating stuff at school is some use after all

[geiristudio]

Yeah I can see that! Thanks for the info. I'm learning a lot in a very short time. I'm glad you guys answer with respect for me (in this example) not knowing everything about the subject.