Frequently Asked Questions

We have tried to list here some common questions that we are asked regularly as a support to our customers. If you have any specific questions, please contact us at sales@camcol.co.uk

General

Q: How do I set up an account with Campbell Collins?
A: Please fill in the online Credit Account Request Form, or contact our sales desk on +44 1438 369466 or email us at sales@camcol.co.uk and one of our team will be happy to discuss opening an account with you.

Q: How do I keep informed of new product releases from Campbell Collins?
A: You can sign up to receive regular product updates from us by dropping us a line at sales@camcol.co.uk, or you can now Follow us on Twitter!

Q: Does Campbell Collins provide free of charge samples for evaluation?
A: In many cases we are happy to provide free of charge samples from many of our suppliers. Full project details would be required to enable us to make a decision on whether or not we can provide them free of charge.

Q: What are your terms and conditions of sale?
A: Please review our online Terms & Conditions.

Q: How do I organise a return of faulty goods for analysis?
A: Before any products are returned to us, it is imperative that you obtain a Returned Materials Authorisation (RMA) number from us. This can be done by completing our online RMA Request Form, by contacting us on +44 1438 369466 or by email at sales@camcol.co.uk giving full details of the parts in question and the reason for return

Q: How do I check if you have stock of a particular part?
A: Our Stocklists are online - lists are updated weekly.

Q: Do your components meet REACH and RoHS directives?
A: Campbell Collins keep logs of all our suppliers' RoHS and REACH statments, and can be supplied on request by calling us at +44 1438 369466 or by emailing us at sales@camcol.co.uk

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Power Supplies

Q: Does Campbell Collins offer any AC/DC units with -40°C operating temperatures?
A: Integrated Power Design's REL series of AC/DC Converters are available with -40°C operation by adding the "-WT" suffix to the part number. Power levels from 70W to 185W are available with up to 4 outputs.

Q: Can I connect DC/DC Converters in series and/or in parallel?
A: Typically, all DC/DC Converters can be connected in series to produce an additive effect in terms of the total output voltage. This can be useful to produce non-standard voltages using individual converters, or to produce "double" the output voltage when using dual output converters (e.g. to produce a single 24V rail from a ±12V device). The maximum output current will be limited by the lowest individual rating of each device used. Reverse diodes across the output of each device will ensure safe operation.

Whether or not you can parallel devices to increase total output power depends on whether or not the converter in question has been specifically designed for parallelling. Some converters (such as Ericsson's PKR series) have load regulation characterisitcs (slope compensation) that means each converter used will naturally share the total output current to within ±10% or better, and so can be very easily directly paralleled.

In other cases however, particularly those using output Synchronous Rectifiers (MOSFETs), an external current share circuit will need to be included to avoid one of the converters shutting down if it has a marginally lower output voltage than the other, and therefore tries to provide the entire current to the load, and goes into over current protection. Further detail and assistance is available from our Technical Sales team at sales@camcol.co.uk.

To parallel for redundancy, series diodes must typically be used in the outputs of each converter to ensure isolation from the bus in the event of a failure of one of the modules.

Q: I am using TO-220 packaged LM78xx Linear Regulators, and have severe thermal problems, do you have alternative solutions offering higher efficiency?
A: The SR78/1000 from Arch Electronics and NSR01 from PowerMate are switching regulators that offer higher efficiency solutions and therefore do not require a heatsink. Please contact us at sales@camcol.co.uk for more details.

 Q: What do I need to do to reduce Conducted EMI when using DC/DC Converters?
A: Our DC/DC Converters switch at frequencies between a few tens of kHz up to 1MHz, and therefore will generate EMI which can be conducted back to the source if not provided with adequate filtering. As each DC/DC Converter is different, we can help guide you in individual applications with suggestions for discrete single stage or multi stage differential or common mode filters, and/or complete filter modules to use in conjunction with the DC/DC Converter. Please contact us at sales@camcol.co.uk or call +44 1438 369466 for more assistance.

Q: Does Campbell Collins offer solutions for Transportation specifications such as EN50155 or RIA12?
A: We can offer Front End solutions to RIA12 from Gaia Converter and MTM Power. Please contact us for more details. EN50155 suitable devices are also available.

Q: Are there any 3D CAD drawings available for Gaia Converter's range of DC/DC Converters & Filters?
A: Yes, these can be found under the Design Tools section of the Gaia Converter Website. Adobe PDF Reader will be required to view the files.

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Capacitors

Q: Does Campbell Collins offer wet tantalum capacitors?
A: Unfortunately, we don't carry any ranges of wet tantalums at the moment.

Q: What basic information should I use to specify a Capacitor?
A: Dielectric material; Rated Capacitance; Tolerance Level; Rated Voltage (DC and/or AC); Max ESR; Operating Temperature; Operating Frequency; Operating RMS Current; Max Pulse Rise Time and/or Max Peak Current.

Q: What is meant by capacitor Ageing in relation to ceramic capacitors?
A: "Ageing" refers to the natural process wherein "X7R", "X5R", "Z5U", & "Y5V" capacitors exhibit a change in capacitance after their temperature is raised above the Curie point for their particular formulation. "C0G" capacitors have a different formulation which does not display any aging characteristic. Thus, C0G capacitors remain constant with time.

Q: Does Campbell Collins offer Polycarbonate capacitors?
A: One of our suppliers - LeClanche - can still supply some Polycarbonate film, as well as superior PPS (PolyPhenyleneSulfide) alternatives. Please contact us for further information on +44 1438 369466 or email us at sales@camcol.co.uk

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Hi-Rel Power Semiconductors & DMS

Q: Are any of the devices from MSK, SSDI or Lansdale ITAR restricted?
A: At the time of writing, only MSK's Rad Hard range of devices intended for space applications are restricted by ITAR Regulations. All other devices typically fall under EAR99 ECCN Classifications, but please contact us to discuss specific questions on +44 1438 369466 or email us at sales@camcol.co.uk

Q: Do I need a speed control or torque control amplifier?
A: In an application where you are looking for servo-like response from the motor, quick and controlled motor reversal, and very tight control around the zero movement point, then a torque controller is recommended. If the system requirement is for controlling speed and positional requirements are not very stringent, then a speed control may suffice. A useful Application Note on the subject from our partner MS Kennedy can be found here

Q: What is the difference between classes of product for MSK devices?
A:  MS Kennedy devices are typically offered in classifications such as Industrial, Class E, Class H, Class K etc. Class E is no longer available for new designs, but the differences in the Classes are explained here