Electronic instrument maker Ametek Inc., of Paoli, today said it bought California Instruments Corp., a privately held company with annual sales of $22 million.

The purchase price was not disclosed. California Instruments, of San Diego, makes programmable power sources for testing electronics.

California Instruments will become part of Ametek's Electronic Instruments Group, which sells instruments to the process and analytical, aerospace, power, and industrial markets.

Ametek has annual sales of $2 billion. Its shares were down 57 cents, to $46.02 in morning trading on the New York Stock Exchange.