TRM Microwave has chosen Cover 2 Sales as their local sales representative for the Marland, Virginia, and District of Columba territory. TRM Microwave’s Product portfolio includes a wide range of RF/Microwave components and integrated subsystem assemblies operating in the range of DC-40GHz, with high power products between 10KHz to 8GHz. These innovative standard and custom-developed units play a critical role in various applications including radar, satellite communication, electronic warfare and threat signal detection. TRM Microwave’s high-tech components have contributed to the success of numerous system architectures through a global base of defense, space and commercial customers.
The addition of TRM Microwave to our line card enhances our RF/microwave product offering, particularly for high performance and high reliability applcations. TRM’s products compliment existing synergistic RF/Microwave solutions from SV Microwave (connectivity) and Johanson Technology (passive discretes).
Please contact Cover 2 Sales for more information on TRM Microelectronics.
Johanson Technology has released their JTISoft simulation software in the Google Play Store (it was previously released in the Apple App Store in April 2019). Johanson’s JTISoft app provides electrical data and charts for each series and capacitance value of their High-Q capacitors. And the app allows you to order samples from anywhere. So if you’re slaving in the prototype lab, debugging your design on the production floor, or celebrating a successful product launch with a cold beverage at the bar, you can order samples directly through the app!
To download from the Google Play Store:
- Open Google Play Store
- Search for “Johanson Technology”
- Select the app
- Tap “Install”
- Follow the onscreen instructions to complete the transaction
Dowloading from the Apple App Store is similar. Searching on “Johanson” will get you to JTISoft and you can install it right from your device.
For additional information, or to order samples or get quotes directly from Johanson, please contact Cover 2 Sales.
Aluminum electrolytic capacitors are used in virtually all types of circuit designs. They are commonly used as filtering devices in power supplies. The following blog post includes a number of guidelines to follow when designing with and using electrolytic capacitors. The material has been paraphrased from United Chemi-con‘s technical topics published on their web sit e here.
- Aluminum electrolytic capacitors should not be used in AC applications.
- In DC applications, always confirm the polarity. If the polarity is reversed, the circuit life will be shortened or the capacitor may be damaged. Generally, an intermittent reverse voltage of 1V DC is allowed. Capacitors used in circuits whose polarity is occasionally reversed or whose polarity is unknown require the use of bi-polar capacitors.
Choose a capacitor whose maximum specified temperature is greater than the operating temperature of the application. This will increase the life of the capacitor. If the temperature rating of the capacitor is less than the temperature of the application, the life of the capacitor will be substantially less than expected or the capacitor could fail catastrophically.
In general, for each 10 degree decrease in operating temperature the capacitor life will double. Conversely, capacitor life will be halved for each 10 degree increase in temperature as determined by the following life expectancy formula.
Lx = Lifetime at actual operating temperature Tx
Lo = Lifetime at maximum rated operating temperature
To = Maximum rated operating temperature (°C)
Tx = Actual operating temperature (°C)
Ripple Current/Load Life
The life expectancy of an aluminum capacitor is not only determined by the ambient temperature, but also by the ripple current. The ambient temperature plus the increase in temperature due to ripple current equals the operating temperature.
Do not apply a ripple current exceeding the rated maximum ripple current allowed for the capacitors as do so will result in shortened capacitor life and may result in the capacitor venting or failing catastrophically.
In many cases capacitor heating due to ripple current is more severe than ambient temperature stress. An acceleration rate of approximately 2x for each 5-10°C temperature increase due to ripple current. The following formula used to determine life expectancy:
Lx = Lifetime under actual ambient temperature and actual ripple current
Lo = Lifetime under maximum rated operating temperature and rated DC voltage with no ripple
To = Maximum rated operating temperature (°C)
Tx = Actual ambient temperature (°C)
T = Inside temperature increase (°C) by actual ripple current
K = Acceleration factor, varied from 5 to 10 by product and conditions
If the applied voltage exceeds the rated voltage of the capacitor, the capacitor may be damaged from an increase in leakage current. When using a capacitor with an AC voltage superimposed on a DC voltage, care must be exercised so that neither the peak value of the AC voltage plus the DC voltage exceeds the rated voltage nor that the minimum AC voltage plus the DC voltage inverts the polarity on the capacitor.
When capacitors are connected in series, the voltage distribution across the series may not be uniform. This is due to the normal DC leakage distribution and should be considered in the design process by using a higher rated voltage capacitor and/or using balancing resistors in parallel with each series capacitor.
General purpose aluminum electrolytic capacitors are covered with a sleeve made of polyvinyl chloride or similar material. In addition to the insulating properties, the sleeving is also used for marking. The aluminum can is not insulated from the cathode, and when the internal element needs to be electrically insulated from the can, capacitors specially designed for these insulation requirements should be used. Also, the dummy terminal is not insulated from the cathode and must not be connected electrically to the anode or cathode.
Incorrect soldering may shrink or break the sleeving of the capacitor. Please read the following information carefully before soldering:
- If the soldering iron comes in contact with the capacitor body during wiring, damage to the polyvinyl sleeve and/or case may result in defective insulation or improper protection of the capacitor element.
- When soldering a printed circuit board, care must be taken so that the soldering temperature is not too high and the wave or soldering time is not too long. Otherwise, there will be adverse effects on the electrical characteristics and the insulating sleeve of aluminum electrolytic capacitors. In the case of miniature aluminum electrolytic capacitors, no harm will occur if the soldering process is performed at less than 260°C for less than 10 seconds.
- During soldering, the sleeve may melt or break if it comes in contact with the circuit board traces. To avoid this problem, do not locate circuit board traces under the capacitor body.
- The sleeving may be melted by solder which migrates up through the terminal holes in the circuit board. To avoid this problem, the same application as stated in item 3 is recommended.
- When soldering adjacent components to the capacitor, preheated lead wires or terminals may tear the capacitor sleeve if these terminals come in contact with the capacitor sleeve. Therefore, mount the capacitors carefully so that the adjacent components’ terminals or lead wires do not come in contact with the sleeve, particularly when mounting on through-hole circuit boards.
For surface mounting capacitors, the reflow soldering conditions are specified in the Surface Mount section of United Chemi-Con’s catalog.
If you have any questions about electrolytic capacitors, please contact Cover 2 Sales for assistance!
Capacitors. So many different types and technologies… but why? What’s unique about them? This blog post attempt to answer those questions about one of the most common capacitor technologies: the aluminum electrolytic capacitor.
The aluminum electrolytic capacitor is a passive component that has traditionally been used for filtering, timing networks, by-pass, coupling and other applications requiring a cost effective, volumetrically efficient and highly reliable component.
An aluminum electrolytic capacitor consists of an anode foil, a cathode foil and separator paper which are wound together and impregnated with an electrolyte. The anode foil has an aluminum oxide layer acting as the dielectric. After the thin aluminum foil (65 to 100 microns) is electrochemically etched to increase the plate’s surface area, the dielectric is produced by anodic oxidation on its surface. The cathode foil, in general, utilizes no oxidation process.
Note that due to the physical design elements and construction, not only does a capacitor have capacitance, but it also has a series resistance and inductance as well as a parallel resistance allowing the flow of current.
The capacitance of aluminum electrolytic capacitors (in microfarads) is expressed by the following equation:
C = 8.855 x 10e-6 x (ES/d)
E = Dielectric constant
S = Surface area of dielectric (cm2)
d = Thickness of the dielectric (cm)
Large capacitance can be obtained when:
- the dielectric constant is high
- the surface area is large
- the dielectric is thin
In aluminum electrolytic capacitors the dielectric constant is only 8 to 10, but the aluminum oxide dielectric layer is extremely thin (about 15 Angstroms per volt). High gain foil produced by the electrochemical etching creates a surface magnification, or gain, as much as 100 times for low voltage foil and 20 to 25 times for high voltage foil. Therefore (and this is a critical benefit of these capacitors):
An aluminum electrolytic capacitor can provide a large capacitance compared to other types of capacitors of the same volume
Nippon Chemi-Con – the parent company of United Chemi-Con – is the world’s largest manufacturer of aluminum electrolytic capacitors. NCC pioneered the development of raw material processing techniques and highly automated production systems. The product improvements of these innovations have dramatically improved circuit design flexibility and led to many new applications for aluminum electrolytic capacitors.
To learn more about aluminum electrolytic capacitors please Contact Cover 2 Sales.