150 uH 1.2 uH and 22 uH molded inductor

[Electro-Ghost]

i know that the molded inductors might not be very hard to find but im on an island so my suppliers are limited, my question is could i some how make a 150uH or if i could just use a 100 uH choke,and if i could somehow make a 1.2 uH and 22 uH to give u a little bit of backround info im usin these for this schematic
**broken link removed**it is a schematic for a small cw transceiver called the pixie2

 

[audioguru]

I see that you double-posted. I answered your other post.

 

[Electro-Ghost]

no u didnt i asked how to mak an inductor

 

[audioguru]

Just buy them.

 

[Electro-Ghost]

i cant,plz just anser my question

 

[audioguru]

You can find out how to make inductors in Google.

 

[RadioRon]

i know that the molded inductors might not be very hard to find but im on an island so my suppliers are limited, my question is could i some how make a 150uH or if i could just use a 100 uH choke,and if i could somehow make a 1.2 uH and 22 uH to give u a little bit of backround info im usin these for this schematic
**broken link removed**it is a schematic for a small cw transceiver called the pixie2

I believe that a 100uH choke would substitute well enough for that 150 uH unit as these values are both relatively high impedance at these frequencies.

As for the smaller values, you can wind them yourself. The ARRL handbook provides a simplified formula for single layer air core inductors that is:

L (uH) = (d^2 x n^2)/(18 x d + 40 x l)

where L is in microhenries (uH)
d is the coil diameter in inches from wire center to wire center
l is the coil length in inches
n is the number of turns.

The coil using this formula must be air core (no plastic or ceramic or metal inside it at all) and you can't overlap windings and it is very important that no turns short to the next turn. This formula is only an approximation and applies to coils with an overall length of greater than 40% of the diameter.

The main problem with this is that a coil of 22 uH is going to be rather large, so if you want to make a very miniature circuit, you may be stuck with trying to make the coil with thin wire. Try playing around with different coil diameters in the formula to see how many turns and therefore how long the coil must be. Also consider that you must use solid copper wire (not stranded) to make the coil and the diameter (or gauge) of the wire should be equal to or larger than AWG#28 for you application in order to carry the expected current without a lot of losses. Thicker wire is better as you will get lower losses and higher Q.

If you have the luxury of choosing which kind of wire to use, then go with enameled copper wire, sometimes called magnet wire. This is copper wire with a very thin coating of clear enamel insulator and it is good because you don't have to worry so much about shorting turns together, and the insulation is very very thin.

 

[Electro-Ghost]

I believe that a 100uH choke would substitute well enough for that 150 uH unit as these values are both relatively high impedance at these frequencies.

As for the smaller values, you can wind them yourself. The ARRL handbook provides a simplified formula for single layer air core inductors that is:

L (uH) = (d^2 x n^2)/(18 x d + 40 x l)

where L is in microhenries (uH)
d is the coil diameter in inches from wire center to wire center
l is the coil length in inches
n is the number of turns.

The coil using this formula must be air core (no plastic or ceramic or metal inside it at all) and you can't overlap windings and it is very important that no turns short to the next turn. This formula is only an approximation and applies to coils with an overall length of greater than 40% of the diameter.

The main problem with this is that a coil of 22 uH is going to be rather large, so if you want to make a very miniature circuit, you may be stuck with trying to make the coil with thin wire. Try playing around with different coil diameters in the formula to see how many turns and therefore how long the coil must be. Also consider that you must use solid copper wire (not stranded) to make the coil and the diameter (or gauge) of the wire should be equal to or larger than AWG#28 for you application in order to carry the expected current without a lot of losses. Thicker wire is better as you will get lower losses and higher Q.

If you have the luxury of choosing which kind of wire to use, then go with enameled copper wire, sometimes called magnet wire. This is copper wire with a very thin coating of clear enamel insulator and it is good because you don't have to worry so much about shorting turns together, and the insulation is very very thin.

what does is it mean when u say no wires short to the next turn also i have a three terminal stereo phone jack an in the schematic it only shows 2 terminals have a look

 

[RadioRon]

what does is it mean when u say no wires short to the next turn also i have a three terminal stereo phone jack an in the schematic it only shows 2 terminals have a look

The inductor is a length of wire wrapped around a circular form to make a spiral. Each time you wrap the wire once around the form, we call that a "turn". It is important that each turn of the spiral be insulated from the ones beside it so that the wire of one turn does not touch another. To do this you can use insulated wire, or you simply inspect the coil carefully to see that there is an air gap between each turn.

Your question about the use of a stereo jack in place of a two terminal jack clarifies that this project is beyond your abilities and I suggest you try something simpler first. However, to answer what appears to be your question, a stereo jack can also be a mono jack if you simply ignore the first ring terminal and use the tip terminal plus the second ring terminal only.

 

[Hero999]

You've got to learn to walk before you can run, or else you'll keep falling, which is both frustrating for you and us; the people who try to help you back up again.