The U.S. stock market's wild recent swings might be stealing attention from the three small companies below. These companies, all members of the S&P SmallCap 600 index, make equipment used to manufacture microchips or other innards for computers and handheld electronics. Sales for each jumped more than 70% last quarter, and are forecast to more than double in their current fiscal year. What's more, sales estimates for them are on the rise, and their shares this year have outpaced the 600 index.

Of course, strong operating momentum doesn't mean shares of these companies will continue rising if the market suddenly drops. Demand for computer equipment is notoriously volatile and subject to changes in consumer spending, which tends to suffer when stocks do poorly. That makes these stocks most appropriate for investors who believe that the market's recent skittishness is nothing to worry about and that the economy is poised for a prolonged recovery, as opposed to those who believe the market's frantic movements are a set-up for a long decline. If, and only if, the former group is right, shares of small technology firms like these should pay off handsomely.

Cohu

Sales growth last quarter: 77%

Today's chip manufacturers use automated test equipment to scan their silicon wafers (from which chips are cut) for dud microcircuits. To do that, they need machines that can hold and manipulate both the test instruments and the wafers. Those machines are called handlers, and tiny Cohu, based a half-hour drive north of San Diego, says it leads the world in sales of them. It achieved that status in part by acquiring Rasco, a major maker of gravity-feed handlers, in 2008. The chip-making business is subject to sudden changes in profitability, and right now Cohu seems to be in a pronounced upswing. Orders at Rasco just hit a quarterly record. Companywide orders are running at their highest level since early 2000. After two years of losses, Cohu is expected to post a healthy profit this year. The company is debt-free and trades at 20 times Wall Street's 2010 earnings forecast -- but just 13 times early forecasts for 2011 profits.

Kulicke & Soffa

Sales growth last quarter: 510%

Ball-bonding refers to the most common way to attach miniscule wires to computer chips, so that their processing power can be put to use by the outside world. Kulicke & Soffa is a leading supplier of expendable tools for the job, and in recent years has bought its way into complementary fields, like wire bonding used in hybrid vehicles and solar panels. Management sees future growth coming from customers "upgrading" their manufacturing processes to use cheap copper rather than costly gold as a bonding agent. (Copper is a better conductor of electricity, but until recent changes in bonding techniques has been too susceptible to oxidation and too likely to damage chips.) It also sees big order potential from light-emitting diode (LED) screens and from wire bonds to connect multiple chips stacked in a single, space-saving package. Sales for Kulicke & Soffa are expected to more than triple during its current fiscal year, which ends Oct. 3. Investors might not fully trust the company's growth spurt; its shares are priced at just four times forecast profits.

Intevac

Sales growth last quarter: 169%

Intevac sells equipment used by companies that make the disks used in hard drives, and it supplies night vision systems to the government. Hard-drive growth is coming from increased sales to emerging economies and from a shift to mobile devices from desktop ones, which has resulted in shorter replacement cycles for gadgets. Also, Intevac is using its disk know-how to expand into solar panels and semiconductors. The company recently announced a record backlog of equipment orders and management raised its sales guidance. Wall Street expects Intevac's sales to more than double this year. Its shares sell for just under 12 times earnings.