kenneth Miller just finished playing the summer stock circuit.

Miller does not sing and dance for a living and is not involved with a theatrical company. He is the president of Penril Corp., the highly successful Rockville-based electronics firm.

But for three weeks, Miller had his own road show as he traveled the country from Atlanta to Beverly Hills trying to sell 670,000 shares of Penril stock, an effort primarily designed to bring the firm more money to continue its acquisition pattern. "We've set the stage to launch to our next plateau, but we had to stop at the fuel station to get some cash," Miller said.

Miller visited groups of Drexel Burnham Lambert Inc. brokers in cities across the country where Penril has only limited recognition. The trip was so successful that the offering oversold and last week picked up an additional 35,000 shares.

The association with Drexel Lambert, the manager of the underwriting group, gives Penril a window on the national investment picture and a means to improve Penril's low national recognition.

In addition, Miller said the Drexel relationship puts the company into a better position to issue bonds eventually. Negotiations with the brokerage house about the possibility of a bond sale are underway, Miller said. The problem, he admits, is the fluctuations that have rocked financial markets in the last year.

"You just can't depend on what the cost of money might be," Miller said in an interview yesterday. "What we've all gone through this year makes financial planning less than easy. This provides us with the basic integrity in terms of the investment community, so we can continue our acquisition pattern. Now we have the cash to make a sizable acquisition." o

Following a pattern established over the period since 1973 when Miller took the Penril position, the 12-year-old company -- which had not been faring well until that time -- is looking to add to the five major purchases it has carried out in the last four years.

"I'd be disappointed if we didn't have one this year," Miller said referring to his hope for an acquisition during the company's fiscal year that started Aug. 1.

The stock sale was designed to free the company from some of its debts and reestablish its $10 million line of credit at Washington's American Security Bank. What the company is looking for now is another firm in related fields that does between $10 million and $25 million in annual sales.

Penril's sales have risen from $1.8 million in 1974 to $22.7 million for fiscal 1979. And the company's stock, which began as an over-the-counter offering in March 1972 and now is traded on the American Stock Exchange, was quoted on Monday at 10 5/8 a share, up from 7 3/8 a share in the fourth quarter of 1978.

A number of factors are responsible for Penril's success, including the fact that the company is well-situated in the generally profitable electronics industry. During the 1979 fiscal year, Penril had sales of $22 million, and in the fiscal year just ended Miller expects that figure to exceed $30 million.

According to Miller, Penril also faces far less competition from imports than others in the industry because of the company's specialized product line.

Penril, in its Rockville Data Communications Division, makes a product called a modem, a device which is used in the sending and receiving of digital information over voice transmission lines, generally telephones. In the last fiscal year alone, the firm's sales of modems rose by between 75 percent and 80 percent.

Another apparent Penril success story is the Epicure Products Inc. subsidiary, a firm purchased by Penril in November 1978. That firm, from a Newburyport, Mass., location, makes audio home speakers under the Epicure and EPI names that are widely regarded as among the finest top-of-the-line stereo equipment.

In fact, that operation appears so successful that Epicure soon will open a new 73,000-square-foot factory near the old site that Miller calls "the most modern loudspeaker facility in the world."

But a thriving company in a solid industry also faces inevitable takeover offers itself. "I don't think a month goes by when we don't receive at least one (offer)," Miller said. "Each opportunity is presented to our board, but so far we believe the best opportunity for our stock is by retaining our independence."

Yet despite the successes of the growth-through-acquisition pattern, Miller says he realizes that the company's first bad acquisition could be it's last. "My big worry is whether the next acquisition is a sound one," Miller said. "Each time we make an acquisition, if we make a bummer, the impact on the company would be significant. If an acquisition turns sour it could put the company on the rocks."