K p electronics manufactures an in-circuit transistor tester, model kp 390m/b which is an in-circuit transistor tester that can test transistor in the circuit as well as outside the circuit without removing it from the circuit, thereby saving valuable time. The tester is mains operated, with a battery operated [9 v, 10 ma] version, kp390b. This tester gives good/bad as well as pnp/npn indication. It is very useful in checking transistors on [smd] printed boards.
