Bobbins (9677001015)
77 BOBBIN GROUND
77 Material
Inductive Components
Open Magnetic Circuit
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Part Number: 9677001015
77 BOBBIN GROUND
Explanation of Part Numbers:
– Digits 1 & 2 = Product Class
– Digits 3 & 4 = Material Grade
– Last digit 8 = Coated Bobbin
Bobbins are an economical and well-proven core design for many applications where relatively low but stable inductance values are required.
For higher frequency designs, use small bobbins in 43 material.
For power applications, bobbins in 77 material are specified for AL and dc bias limits.
Bobbins in Figures 2-5 can be supplied with a uniform thermo-set plastic coating which can withstand a minimum breakdown of 500Vrms. This coating will change the dimensions a maximum of 0.5 mm (0.020″). The last digit of the thermo-set plastic coated part is an “8”.
For any bobbin requirement not listed in the catalog, please contact our customer service group for availability and pricing.
Weight: 6.7 (g)
| Dim | mm | mm tol | nominal inch | inch misc. |
| A | 9.55 | -0.15 | 0.373 | _ |
| B | 19 | ±0.70 | 0.748 | _ |
| D | 12.7 | ±0.15 | 0.5 | _ |
| F | 4.65 | +0.20 | 0.187 | _ |
| G | 1 | +0.25 | 0.044 | _ |
| H | 1.03 | +0.10 | 0.043 | _ |
Chart Legend
AL : Inductance Factor 
, Nl : Value of dc Ampere-turns, AW:Winding Area,
N/AWG : Number of Turns/Wire Size for Test Coil
| Electrical Properties | |
| AL(nH) | 39 ±10% |
| AL min. @ Nl (At) | 33 - 125 |
| N/AWG | 75/24 |
| Aw(cm2) | 0.3 |
Bobbins are tested for AL value at 1kHz < 10 gauss.
A MnZn ferrite for use in a wide range of high and low flux density inductive designs for frequencies up to 100 kHz.
Available in 77 material:
Pot Cores
E&I Cores
U Cores
Rods
Toroids
Bobbins
77 Material Characteristics
| Property | Unit | Symbol | Value |
| Initial Permeability @ B < 10 gauss | µi | 2000 | |
| Flux Density @ Field Strength | Gauss Oersted |
B H |
5100 5 |
| Residual Flux Density | Gauss | Br | 1800 |
| Coercive Force | Oersted | Hc | 0.25 |
| Loss Factor @ Frequency | 10 -6 MHz |
Tan δ/ µi | 15 0.1 |
| Temperature Coefficient of Initial Permeability (20 -70°C) | %/°C | 1.2 | |
| Curie Temperature | °C | Tc | >200 |
| Resistivity | ohm-cm | ρ | 100 |
**** Characteristic curves are measured on standard Toroids (18/10/6 mm) at 25°C and 10 kHz unless otherwise indicated. Impedance characteristics are measured on standard shield beads (3.5/1.3/6.0 mm) unless otherwise indicated.
Material Safety Data Sheet (MSDS)
Click here to download Complex Permeability vs. Frequency (CSV)
Ferrite Material Constants
Storage and Operating Temperature
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