Metric range of thread diameter through capacitor thread size:
See the table below for the comparison of thread diameters of M3, M4, M5, M6, M8 and M9 imported filters.
Types of feedthrough capacitors
Type c filter
C-type filter is composed of three-terminal capacitors or through capacitors, which is suitable for suppressing high-frequency signals. Type c filter can be used at both ends.
It is considered as a low impedance connection to a high impedance source and load.
LC filter
The LC filter includes an inductor and a capacitor, which can provide high input impedance or
According to the installation direction of the circuit, low input impedance is provided. LT circuit is suitable for high impedance load and low impedance source.
LB circuit is suitable for low impedance load and high impedance source.
π type filter
π-type filter consists of two capacitors and an inductor, and its input and output are low impedance. π circuit, because
There are many components, so its insertion loss characteristics are better than those of C type and LC type. However, in the switching circuit, "ringing" may occur.
So please pay attention when using.
π-type filter with transient suppressor
This π -type filter adds a transient suppressor at its input. It has good high frequency suppression performance and can prevent voltage spikes at the same time.
Test filter
T-type filter includes two inductors and a capacitor. Its two ends are high impedance, and its insertion loss performance is similar to that of π filter.
But it is not easy to ring, so it can be used in switching circuits.
Multi-stage filter double T-type filter
Multi-stage filter is a high performance filter, which is designed for circuits with low source impedance and load impedance, and can also be used for high insertion loss requirements.
Other environment. The inductance at the input of the filter is the best match of MILSTD-46ID (GJB-151A) test equipment.
Different filter connection circuits have different filtering characteristics. The filtration curve of C-type filter is steeper than that of C-type filter, while that of Pi-type and double T-type filters is steeper.
Used when the frequencies of effective signal and interference information are close.
Comparison of thread diameters of imported filters;
Matters needing attention in installation of through capacitor
The core of the filter is a disk-shaped multilayer or tubular ceramic capacitor. Like other ceramic objects, it will be affected by sudden changes in temperature.
Damage caused by mechanical vibration and overvoltage. When installing the through-hole filter on the board, the guide pin of the filter must be welded and formed.
Carefully minimize all kinds of pressure.
Installing threaded straight-through filter
Installation rotational force—When installing the filter on the partition or panel, the recommended installation rotational force relative to the housing should be used. This is very important.
Otherwise, the internal capacitor may be damaged due to the deformation of the shell. When installed in threaded holes, the recommended maximum installation torque is.
Use 50% nuts.
Installation tool-hexagonal filter should be installed with a suitable sleeve. The following methods are adopted for the circle (pliers are not allowed)
Tool installation to avoid damaging the filter).
A circular filter with a groove at the top is screwed into the threaded hole with a simple special tool.
Grounding-In order to ensure the normal operation of the filter, the shell of the filter must be fully connected with the grounding of the panel to prevent interference.
Provide effective access. Adhesive locking is not recommended. If it is used, it should be used after installing the filter.
Minimum plate thickness-users should note that sometimes the through-core filter has an outlet slot between the thread and the mounting edge of the shell. When loading
When the thickness of the plate is less than the length of the decompression tank, there will be problems in the tight fit of the threaded holes and the positioning of the filter. Therefore,
Whenever possible, the thickness of the panel should be greater than the length of the decompression tank.
Maximum plate thickness-this indicator is used to ensure that the nut can be fully toothed, including the use of washers.
Install direct welding pass-through filter
The welding process should be controlled so that the filter will not break due to sudden thermal shock.
During preheating and heating, the speed should be kept at 2℃/s. Actually, depending on different substrates and components, the temperature is 1.5 ~ 4℃/ sec.
There are examples of successful welding in this range.
It is very useful to use soaking zone before welding. This makes the temperature of the substrate uniform without deformation. After cooling, any substrate
Deformation recovery will produce stress that damages the filter.
The welding material may be SN60, SN62 or the like.
The welding time should be shortened as far as possible, and the temperature should be controlled at no more than 250℃ (suitable for welding perforation series).
Natural cooling should be adopted when cooling to room temperature. Let the temperature difference stress of welding points relax one by one to avoid airflow cooling. Forced airflow cooling will bring
Temperature difference damage, cleaning with coolant immediately after welding will damage ceramic capacitors.
Terminal welding
Whether it is threaded installation or direct welding, the following points should be paid attention to when welding the guide pin:
The soldering iron end temperature should not exceed 300℃, and the longest soldering time should be 3 ~ 5 seconds, so as to minimize the risk of thermal shock damaging the capacitor.
The welding material may be SN60, SN62 or the like.
It is particularly important to use the radiator as much as possible between the welding point and the shell, especially in the case of long welding time.
Dressing of guide pin bending
The bending of the filter guide pin should not be carried out within 4mm from the epoxy seal, and the guide pin should be supported during trimming.
Product design of feedthrough capacitor: RTF-66-001-150GI4.
Nominal capacitor working current rated voltage working temperature Installation method Thread size Other
Rtf-66-001150g I 4
C0.015μ f1a50v-55-+125℃ bolt M4
Types of feedthrough capacitors
Chip filter
There are two kinds of patch and lead, which are small in size and can be used for surface mounting, saving PCB space and installation time.
Resin sealed packaging filter
This kind of filter can be divided into two types according to different installation methods: welding type and threaded type, and the circuit structure is C type.
L-type, LC-type, Pi-type and T-type can be selected.
Glass sealed packaging filter
Glass packaging is suitable for harsh environment and has high filtering performance, which is widely used in military and aviation fields. circuit configuration
There are C type, LC type, Pi type, T type and double T type.
Filter array
Filter array is a combination of multiple welded filters, and multiple filters with different filtering characteristics can be selected according to customer requirements.
Soldered on the same substrate. Filter arrays can be plugged in rows, which is very convenient to install and use.
Filter connector
A filter connector is a filter added to a standard connector. Filter connector is used for I/O interface, which can provide good
The electromagnetic interference suppression effect is good. There are many types of filter connectors, such as D-type and circular, which can be docked with standard connectors.
mains filter
The power filter is used in the power supply system of the circuit, which can suppress the electromagnetic interference conducted to the circuit through the power line, and can also
It is the most economical choice to suppress the interference generated by the circuit and feed it back to the power supply.
Thirteen. Characteristics and applications of feedthrough capacitors and feedthrough filters;
Welding straight-through filter
Welding straight-through filter is the most ideal product for narrow installation space;
Usage: mainly used for filtering signals, data lines and AC power lines;
Telecommunication equipment, transmission equipment, microwave filter, industrial computer, composite circuit filter element;
Small size: effective use of space; Rated voltage: up to 750VDC；;
A variety of circuit structures: C-type, π-type and L-type circuits can be provided;
High temperature structure: it can prevent backflow during installation;
Certification: Filters that can be certified by MIL-F- 15733 QPL and MIL-C-1015 (CK99);
Resin sealing bolt straight-through filter
The nut and washer of the resin sealing bolt through the filter can be easily installed in the through hole position;
The two ends of the solid shell are sealed with resin, which has good environmental protection;
Uses: mainly used for filtering signals, data lines and DC power lines; Wherein micro-extrusion mounting or screw mounting is applied in non-extrusion.
Ideal for welding, suitable for microwave and other high frequency applications;
Voltage: up to 2500VDC/240VAC Certification: It can be used for MIL-F- 15733 certified products.
Circuit structure: C type, L type and Pi type.
High current and high voltage resin sealed straight-through filter
Purpose: High current filter is mainly used for high current switching power supply and DC charging system;
High-voltage filter is mainly used for high-voltage power supply, with solid bolt structure and convenient installation;
Features: high current can reach 100 amp; The voltage can reach 2500 volts DC and 240 volts AC @ 400 Hz.
Glass sealed high performance straight-through filter
This series of filters adopts glass seal and has excellent EMI filtering performance; For those who still have requirements in harsh environment.
This product is the best choice for reliable filtering, and can be used for broadband high-performance EMI filtering above 10KHz to 10GHz.
Glass sealing series has high moisture resistance and corrosion resistance, and can resist other adverse environmental effects that may be encountered in military applications.
Applications: power supply, signal line, rocket ignition device, aircraft, military communication, medical equipment, multi-stage filtration;
Optimal design: various sizes and shapes and C, L and π circuits can be selected to instantly suppress π, T and&; TT circuit is optional;
Reliability: manufactured according to MIL-F- 15733 and MIL-F-2886 1 standards, meeting QPL requirements;
Based on MIL-F-2886 1 and "S" class space applications.
FED/MIL certification: Meets MIL-F- 15733 and MIL-F-2886 1 standards.
Characteristics: the insertion loss range is 1MHZ- 18GHZ.
Capacitance and temperature characteristics: 1.4μF NPO, X7R, Z5U
Temperature range: -55℃-+ 125℃ Maximum voltage value: 400VDC 240VAC@400HZ Maximum current: 30a.