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SQP CR-L Ceramic Cased Cement Resistor 20W 1000 Ohm 5% For Charger Aging
What is cement resistor ?
In fact, cement resistor does not have cement itself, but why is it
called cement resistance? (Wirewound or metal oxide film) core,
package filler, soldering lead and ceramic shell, etc., and some
have metal brackets outside. Cement resistor packages generally
have two types: horizontal and vertical.
Cement resistors are resistors that are potted with cement, that
is, the resistance wire is wound on a non-alkali heat-resistant
ceramic part, and the outside is protected by heat-resistant,
moisture-resistant and corrosion-resistant materials, and the
wire-wound resistor body is placed in a square shape. Porcelain
frame, with special non-flammable heat resistance. Its function is
the same as that of general resistance, but it can be used in
occasions with large current, such as being connected in series
with the motor to limit the starting current of the motor, and the
resistance value is generally not large. Cement resistors have the
characteristics of large size, shock resistance, humidity
resistance, heat resistance, good heat dissipation, and low price.
They are widely used in power adapters, audio equipment, audio
frequency dividers, instruments, meters, televisions, automobiles
and other equipment.
Dimension Of The Cement Resistor 20W
| Watt | Dimensions(mm) | Resistance Range(Ω) | ||||
| L | W | H | Φd±0.05 | Wire Wound | Metal Oxide Film | |
| 1W | 14±1.0 | 6.5±1.0 | 6.5±1.0 | 0.50 | 0.1Ω~22Ω | 25Ω~56KΩ |
| 2W | 18±1.0 | 7.0±1.0 | 7.0±1.0 | 0.50 | 0.1Ω~22Ω | 25Ω~56KΩ |
| 3W | 22±1.0 | 8.0±1.0 | 8.0±1.0 | 0.68 | 0.1Ω~47Ω | 50Ω~100KΩ |
| 5W | 22±1.0 | 9.5±1.0 | 9.5±1.0 | 0.68 | 0.1Ω~47Ω | 50Ω~100KΩ |
| 7W | 35±1.5 | 9.5±1.5 | 9.5±1.5 | 0.68 | 0.5Ω~330Ω | 450Ω~100KΩ |
| 10W | 48±1.5 | 9.5±1.5 | 9.5±1.5 | 0.68 | 0.5Ω~450Ω | 470Ω~100KΩ |
| 15W | 48±1.5 | 13±1.5 | 13±1.5 | 0.68 | 1Ω~500Ω | 510Ω~100KΩ |
| 20W | 63±1.5 | 13±1.5 | 13±1.5 | 0.68 | 1Ω~600Ω | 620Ω~100KΩ |
| 30W | 75±2.0 | 19±2.0 | 17±2.0 | 0.68 | 1Ω~600Ω | 620Ω~100KΩ |
| 40W | 89±2.0 | 19±2.0 | 19±2.0 | 0.68 | 1Ω~600Ω | 620Ω~100KΩ |
Structure diagram Of The Cement Resistor 20W
The construction of resistor Cement Type Resistors shall be as
follow:
NO | Item | Material |
| 1 | Ceramic core | High alumina ceramic is used. |
| 2 | Resistor element | The resistor element shall consist of metal oxide film or Resistance wire (Exemple:CN49W Φ1.0mm) . |
| 3 | Terminal | Tinned iron cap. |
| 4 | Connection | The lead wire,which is plated with solder,shall be mounted to the caps by welding process. |
| 5 | Lead wire t | Soldered or tinned annealed wire. |
| 6 | Silicon cement | Silicon resin is used. Accord with UL-94V-0 Nonflammable specification |
| 7 | Ceramic case | High thermal conductivity |
Features Of The Cement Resistor 20W
1, shock resistance, moisture resistance, heat resistance and good
heat dissipation, low price and other characteristics.
2. Complete insulation, suitable for printed circuit boards.
3. Winding the wire on the porcelain rod and then welding the joint
to produce accurate resistance value and prolong life.
4. The high resistance value is made of metal oxide film body (MO)
instead of winding.
5. Excellent heat resistance, small temperature coefficient of
resistance, and linear change.
6. It is resistant to short-time overload, low noise, and the
resistance value has not changed over the years.
7. Good explosion-proof performance and protection.
Shortcoming Of The Cement Resistor 20W
The disadvantage of cement resistance is that it is large in size,
has high heat generation during use, is easy to dissipate, and
often cannot meet the requirements of precision and stability. For
high-power, small-volume resistors, or high precision and fast heat
dissipation, cement resistors can be replaced with JEPSUN power
resistors, 3W, 20W, 30W, 50W, 100W, and even more power can be
achieved, using TO-220 , TO-247 package, high accuracy, strong
stability, fast heat dissipation. Cement resistor housings are
generally made of ceramics, and their main components are: alumina
Al2O3, commonly known as corundum porcelain, which has the
characteristics of fast heat dissipation and high strength.
Function Of The Cement Resistor 20W
1: The function of the power supply current limiting, usually
connected to the main voltage +300V and the E and C poles of the
power switch tube, the function is that the power supply will not
damage its components when it is turned on.
2: The starting resistance of the power supply, the resistance
between the power tube and the starting circuit is connected to
+300V, the voltage drop and current are large, so the cement
resistance with high power is also used.
3: The peak pulse absorption circuit between the power switch tubes
B, C, and E also uses a high-power cement resistor, which also
protects its power switch tube.
4: The current protection circuit is generally connected between
the E pole of the power switch tube and the ground. When it is
working normally, its resistance can be ignored, because the
resistance of the resistance is very small and there is no current,
only when the circuit itself and the load are short-circuited. , in
order to increase the current of the E pole of the power switch
tube, so that the protection voltage is generated at both ends of
the resistance to start the related circuit.
Application Of The Cement Resistor 20W
Widely used in power adapters, audio equipment, audio frequency
dividers, instruments, meters, televisions, automobiles and other
equipment
Cement resistors are usually used in occasions with high power and
high current, including 2W, 3W, 5W, 10W or even more power, such as
air conditioners, TV sets, and other electrical appliances with
power above 100 watts, basically all use cement resistance.
