Test Coils for Reed Switches

Using a test coil is one of the most accurate ways of measuring a reed switch or a reed sensor's sensitivity. The number of turns in the test coil multiplied by the current at which the switch closed gives the ampere-turn (AT), which is a direct measure of sensitivity. Care should be taken to see the the test coil is always used vertically so that the earth's magnetic field does not affect the measurement, and that the reed switch or reed sensor under measurement is always centered to the test coil. No ferro-magnetic crocodile clips, connectors or mounting parts should be nearby.

Cylindrical Test Coils

All dimensions in mm
Test Coil	001	002	003	004	005
A	53.3	21.0	12.0	27.8	19.0
B	50.8	19.0	10.0	25.4	15.0
C	7.6	4.3	3.3	8.7	3.7
D	5.6	3.4	2.3	2.4	2.9
E	14.1	7.7	11.0	17.2	11.0
Wire Dia.	0.090	0.050	0.060	0.100	0.071
Turns	10000	5000	5000	5000	5000
Res.Ω	845	740	600	404	450

Rectangular Test Coils

All dimensions in mm
Test Coil	TCP 3001	TCP 3002	TCP 3003	TCP 3004
A	13.5	23.3	42.5	42.5
B	7.0	19.7	36.5	36.5
C	8.0	6.8	14.8	15.8
D	6.0	6.2	13.8	13.8
E	14.0	14.8	25.0	25.0
F	18.0	20.6	28.6	35.6
G	12.0	12.2	14.6	22.8
H	10.0	11.6	13.6	20.8
Wire Dia.	0.050	0.080	0.150	0.150
Turns	5000	10000	5000	5000
Res. Ohms	2000	1900	290	440

Download this data sheet

Miniature Standard Formations Test Coils Magnets Production Crosslink PC Cards Notes

Reed Relays and Electronics India Limited, 2008

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