Use variable capacitors to filter out frequencies that are not part of the main signal. These components generally have metal plates to hold different charges. A variable capacitor is a perfect tool in situations such as radio tuning, where applications need adjustment in capacitance.

When looking at variable capacitors for purchase, it's important to consider the many different styles including: vacuum variable capacitors, a high-power variable capacitor and the air variable capacitor. See which one works best for you.

1. Vacuum variable capacitors, which use a high vacuum rather than air or any other insulating material as the dielectric, allow for a higher voltage rating.

2. A high-power variable capacitor is advantageous in radio frequency applications.

3. An air variable capacitor, which consists of a rotating blade that varies capacitance with movement and a stationary blade, supports the blade with an electrically insulating framework.

Action Steps
The best contacts and resources to help you get it done

Lower the variable capacitor price with used or refurbished equipment

Instead of hunting through variable capacitors for sale, use rented or refurbished equipment. This not only saves on initial costs, but also gives you a chance to test the products to see what works best before making a solid purchase. Consider renting from companies who offer an option to buy, if you are satisfied with the capacitor.

I recommend: Test Equipment Connection offers refurbished electronic test equipment including variable capacitors. This company supplies products for customers around the world, carries thousands of products and also gives you the option of trading in or selling your used equipment. If you are looking for equipment that looks as good as it works, consider AccuSource Electronics’ used test equipment. The company prides itself in offering prices well below the competition and offers operation manuals and accessories.

Consider variable capacitor manufacturers who offer a variety in product

When you buy variable capacitors look for a variable capacitor manufacturer that carries numerous designs to find the equipment which best suits your purposes. Specifically look for companies constantly expanding inventory, and ask what new products are available in the near future.

I recommend: Newark claims to have the electronic industry's broadest selection of electronics, including variable capacitors. It offers live support online. AVX, an ISO 9001:2000 certified manufacturer of capacitors, includes a product line that covers a variety of capacitors from ceramic to disc to variable.

Have a manufacturer design custom air variable capacitor kits and other variable capacitor products

Sit down and consult with a manufacturer about specifications and expectations when you buy variable capacitors. Make sure the manufacturer offers support for the product.

I recommend: Oren Elliott Products is a manufacturer of capacitors that specializes in custom designs. It consults with clients from various industry applications including microchip fabrication, optical and radio. Tedss.com offers customers unique components for their specialized needs. It prides itself in low prices and customer satisfaction.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  When considering variable capacitors, remember the charges in the capacitors change according to the amount of space in between the plates.