Toroids, Beads, & Baluns

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Ferrite toroid cores are used for low power tuned circuits and especially for wideband transformers and baluns for transistor coupling and antenna matching. They have high permeability so you get high inductance with few turns. The low frequency cores are used in switched-mode power supplies. Many Amateur Radio QRP transmitters and receivers will have at least one of these or several. 

The frequency ranges listed in the table are those recommended for tuned circuits. For wideband transformers the top frequency is ten times higher.


Wound Toroid
To find the turns required for a desired inductance use the formula at the right. Turns=1000


Unwound Toroid

CHART SHOWING mH PER 1000 TURNS

CORE
SIZE
MIX 43
µ = 850
.01 - 1
MHz
MIX 61
µ =125
.2 - 10
MHz
MIX 75
µ = 5000
.01-1
MHz
MIX 77
µ = 1800
.001 - 2
MHz
SIZE
0D
(in)
SIZE
ID
(in)
SIZE
HT
(in)
FT23
FT37
FT50
FT82
FT114
FT140
FT240
188
420
523
557
603
1060
1240
25
55
68
73
79
140
173

-
2210
2750
3000
-
-
-

396
884
1100
1170
1270
2250
2740
0.23
0.37
0.50
0.82
1.14
1.40
2.40
0.12
0.19
0.28
0.52
0.75
0.90
1.40
0.06
0.12
0.19
0.25
0.30
0.50
0.50
Pricing and Ordering

FT23 Type

FT37 Type

Part No.

Price

 QTY

Part No.

Price

 QTY
FT23-43 $0.60 FT37-43 $0.70
FT23-61 $0.60 FT37-61 $0.70
FT23-77 $0.60 FT37-75 $0.70
      FT37-77 $0.70

FT50 Type

FT82 Type

Part No.

Price

 QTY

Part No.

Price

 QTY
FT50-43 $0.85 FT82-43 $1.30
FT50-61 $0.85 FT82-61 $1.30
FT50-75 $0.85 FT82-75 $1.95
FT50-77 $0.85 FT82-77 $1.30

FT114 Type

FT140 Type

Part No.

Price

 QTY

Part No.

Price

 QTY
FT114-43 $2.30 FT140-43 $3.50
FT114-61 $2.30 FT140-61 $3.50
FT114-77 $2.30 FT140-77 $3.50

FT240 Type

Part No.

Price

 QTY
FT240-43 $8.75
FT240-61 $8.75
FT240-77 $8.75

BALUNS and WIDEBAND CORES

Dimensions in inches; AL value in mh/1000 turns based on hole to hole winding.
PART NO.
OD
ID
HGT
TH
TYPE
AL

DIMENSIONAL DRAWING

BN-43-202
BN-43-2302
BN-43-2402
BN-61-202
BN-61-2302
BN-61-2402
BN-61-1802
BN-73-202
BN-73-2402		 0.525
0.136
0.28
0.525
0.136
0.28
0.25
0.525
0.275		 0.15
0.035
0.07
0.15
0.035
0.07
0.05
0.15
0.07		 0.55
0.093
0.24
0.55
0.093
0.24
0.24
0.55
0.24		 0.295
0.08
0.16
0.295
0.08
0.16
---
0.295
0.16		 ONE
ONE
ONE
ONE
ONE
ONE
TWO
ONE
ONE		 2890
680
1277
425
100
280
310
8500
3750

Pricing and Ordering

Part No.

 Price QTY

Part No.

 Price QTY
BN43-202 $0.65 BN61-2402 $0.55
BN43-2302 $0.55 BN73-2402 $0.55
BN43-2402 $0.55 BN73-202 $0.75
BN61-202 $0.65    
BN61-2302 $0.55      
FERRITE BEADS
Part No.

Price

 QTY Part No.

Price

 QTY
FB43-101

$0.32

      
FB43-801 $0.44 FB64-2401 $0.50
FB43-2401 $0.50 FB73-101 $0.32
FB43-5111 $0.50 FB73-801 $0.44
FB64-101 $0.32 FB73-2401 $0.50
FB64-801 $0.44 FB75-101 $0.34
FERRITE RODS
Part No. Material Size

Price

 QTY
FR4-33 #33 1/2" Diameter X 4" Long $9.90
FR4-61 #61 1/2" Diameter X 4" Long $9.90
FR7-33 #33 1/2" Diameter X 7-1/2" Long $20.95
FR7-61 #61 1/2" Diameter X 7-1/2" Long $20.95

Q-DOPE
Solution of pure polystyrene in solvents. Dries fast and leaves a clear, 
protective coating on toroids, coils and transformers, with no or minimal 
effect on inductive values. May also be used as a cement for molded or 
fabricated items made of polystyrene.

THIS ITEM CAN ONLY SHIP UPS GROUND. NO US MAIL SHIPPING. 
NO SHIPMENTS OUTSIDE OF THE UNITED STATES, INCLUDING 
ALASKA AND HAWAII.

10-3702................$7.95 QTY:

SCOTCH 27 GLASS CLOTH TAPE
High temperature tape with thermosetting pressure sensitive adhesive. It is
recommended for the wrapping of larger Toroid cores because of its excellent
insulating properties. 1/2" X 66 Ft.
MM27................$10.75 QTY:

**Disclaimer:
          Toroids are very fragile. We do not like to ship them overseas due to the rough handling of the packages. We do ship them however if a customer still wishes us to. The customer assumes all responsibility for the received package. Ocean State Electronics shall not be responsible for any broken items received.  Broken items will not be replaced or issued credit for.