MELF RESISTORS
• Resistors shall have a power rating based on continuous full
load operation at an ambient temperature of 70
ํ
c
•For temperature in excess of 70
℃
, the load shall be derated
•Resistors shall have a rated direct-current (DC) continuous
working voltage
•an approximate sine-wave root-mean-square (RMS) alternating-
current (AC) continuous working voltage at commercial-line
frequency and waveform curresponding to the power rating
Website: www.royalohm.com
Email: info@royalohm.com (Thailand
泰國ประเทศไทย)
info-sz@royalohm.com.cn (China Shenzhen
中國深圳
ประเทศจีน เซินเจิ้น
)
Part Number System
Explanation of Part Number System
(MELF Carbon Film Resistors)
1
M
2
C
3
2
4
7
5
S
6
2
7
J
8
0
9
1
10
0
11
1
12
T
13
2
14
0
Product Type:
MC24 = MELF Carbon Film type 0204
MC27 = MELF Carbon Film type 0207
Resistance Value:
E-24
series: the 1 digit is"0",
the 2 & 3 digits are for
the significant figures of the
resistance and the 4 indicate
the number of zeros following:
"J" ~ 0.1, "K" ~ 0.01
Ex.: 4.7Ω ~ 47J, 4.7KΩ ~ 472
th
nd
rd
st
Wattage:
Normal size: Small size:
W8 = 1/8W
W4 = 1/4W
S4 = 1/4W-S
S2 = 1/2W-S
Packing Type:
Tolerance:
G = ± 2%
J = ± 5%
T = Tape/Reel
Packing Quantity:
2 = 2,000pcs
3 = 3,000pcs
Sample:
MELF Carbon Film type 0204 1/4W-S +/- 5% 100Ω Tape/Reel 3,000
→
MC24S4J0101T30
MELF Carbon Film type 0207 1/4W +/- 5% 100Ω Tape/Reel 2,000
→
MC27W4J0101T20
MELF Carbon Film type 0207 1/2W-S +/- 5% 100Ω Tape/Reel 2,000
→
MC27S2J0101T20
B = 2,500pcs
Addition Information:
0 = NIL
Ratings:
Type
Power Rating
Max. Working Voltage
Max. Overload Voltage
Temperature Range
Ambient Temperature
MECF 0204
0.25W (1/4W-S)
250 V
500 V
MECF 0207
0.25W (1/4W)
300 V
600 V
-55℃½ +155℃
70
℃
MECF 0207
0.50W (1/2W-S)
300 V
600 V
1 Power rating:
Resistors shall have a power rating based on continuous full load operation at an
ambient temperature of 70
℃.
For temperature in excess of 70
℃
, the load shall be
derated as shown in the figure 1.
2 Voltage rating:
Resistors shall have a rated direct-current (DC) continuous working voltage or
an approximatesine-wave root-mean-square (RMS) alternating-current (AC) continuous working
voltage at commercial-line frequency and waveform curresponding to the power rating ,
as determined from the following formula :
RCWV =
√
P x R
Were : RCWV = Rated DC or RMS AC continuous working voltage at commercial-line frequency and
waveform (volt)
P = Power Rating (watt)
R = Nominal Resistance (ohm)
In no case shall the rated DC or RMS AC continuous working voltage be greater
than the applicable maximum value.
Figure 1.
Construction :
No.
1
2
3
4
5
Name
Basic Body
Resistance Film
End Cap
Coating
Color Code
Material
Rod Type Ceramics
Carbon Film
Steel (Tin plated iron surface)
Insulated resin ( Color : Ivory )
Epoxy Resin
Power rating and dimensions
Dimension :
Dimension (mm)
Type
MECF 0204
MECF 0207
MECF 0207
Power Rating :
Type
MECF 0204
MECF 0207
MECF 0207
Power Rating at 70
℃
0.25W(1/4W-S)
0.25W(1/4W)
0.50W(1/2W-S)
Tolerance %
±5
±5
±5
Resistance Range
1Ω ~ 1MΩ
1Ω ~ 1MΩ
1Ω ~ 1MΩ
Power
Rating
0.25W
0.25W
0.5W
L
3.5±0.2
5.9±0.2
5.9±0.2
C Min
0.5
0.5
0.5
D1
1.40±0.15
2.2±0.1
2.2±0.1
D2 Max
1.55
2.4
2.4
D3 Max
1.25
2.1
2.1
Part Number System
Explanation of Part Number System
(MELF Metal Film Resistors)
1
M
2
2
3
7
4
W
5
4
6
F
7
F
8
1
9
0
10
0
11
0
12
T
13
2
14
0
Product Type:
M24 = MELF Metal Film
Resistance Value:
E-24
series: the 1 digit is"0",
the 2 & 3 digits are for
the significant figures of the
resistance and the 4 indicate
the number of zeros following:
"J" ~ 0.1, "K" ~ 0.01
Ex.: 4.7Ω ~ 47J, 4.7KΩ ~ 472
E--96
Series: the 1 to 3
st
rd
th
nd
rd
st
type 0204
M27 = MELF Metal Filmx
type 0204
Wattage:
Normal size: Small size:
W8 = 1/8W
W4 = 1/4W
Tolerance:
B = ± 0.1%
C = ± 0.25%
D = ± 0.5%
F = ± 1%
G = ± 2%
J = ± 5%
digits
S4 = 1/4W-S
S2 = 1/2W-S
are significant figures of
resistance and the fourth
one denotes number of zeros
following:
Ex.: 1.33KΩ = 1331
PPM requirement:
A = ± 10PPM
B = ± 15PPM
C = ± 25PPM
F = ± 50PPM
G = ± 100PPM
J = ± 200PPM
Packing Type:
T = Tape/Reel
Packing Quantity:
2 = 2,000pcs
3 = 3,000pcs
Sample:
MELF Metal Film type 0204 1/4W-S +/- 1% 50PPM 100Ω Tape/Reel 3,000
→
M24S4FF1000T30
MELF Metal Film type 0207 1/4W +/- 1% 50PPM 100Ω Tape/Reel 2,000
→
M27W4FF1000T20
MELF Metal Film type 0207 1/2W-S +/- 1% 50PPM 100Ω Tape/Reel 2,000
→
M27S2FF1000T20
B = 2,500pcs
Addition Information:
0 = NIL
Ratings:
Type
Power Rating
Max. Working Voltage
Max. Overload Voltage
Temperature Range
Ambient Temperature
MEMF 0204
0.25W (1/4W-S)
200 V
400 V
MEMF 0207
0.25W (1/4W)
250 V
500 V
-55℃½ +155℃
70
℃
MEMF 0207
0.50W (1/2W-S)
250 V
500 V
1 Power rating:
Resistors shall have a power rating based on continuous full load operation at an
ambient temperature of 70
℃.
For temperature in excess of 70
℃
, the load shall be
derated as shown in the figure 1.
2 Voltage rating:
Resistors shall have a rated direct-current (DC) continuous working voltage or an approximate
sine-wave root-mean-square (RMS) alternating-current (AC) continuous working voltage at commercial-
line frequency and waveform curresponding to the power rating , as determined from the
following formula :
RCWV =
√
P x R
Were : RCWV = Rated DC or RMS AC continuous working voltage at commercial-line frequency and
waveform (volt)
P = Power Rating (watt)
R = Nominal Resistance (ohm)
In no case shall the rated DC or RMS AC continuous working voltage be greater
than the applicable maximum value.
Figure 1.
Construction :
No.
1
2
3
4
5
Name
Basic Body
Resistance Film
End Cap
Coating
Color Code
Material
Rod Type Ceramics
Metal Film
Steel (Tin plated iron surface)
Insulated epoxy resin ( Color : Blue )
Epoxy Resin
Microcontroller MCU
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