The directory contains all the main categories of transistors: bipolar silicon and germanium transistors, pre-biased bipolar transistors, junction and metal-oxide-semiconductor field effect transistors (MOSFET), insulated-gate bipolar transistors (IGBT). There are also transistor assemblies: dual bipolar transistor, dual pre-biased bipolar transistors, dual-channel mos-field effect transistors (MOSFET) and dual-channel insulated-gate bipolar transistors (IGBT). The directory provides two ways to search for transistors in the database - by parameters and by name. Search by name is convenient if you have a transistor and need to find out its characteristics. To do this, you need to type characters from the name of the transistor, while the table below will immediately display those transistors, in the name of which there is this sequence of characters. To search for parameters, first select the appropriate category of transistors. Then you specify the ranges of values of the necessary parameters for the selected type of transistors. Transistors that meet the specified parameters will also be displayed in the table below. By clicking on one of the lines, you can open a page with a detailed description of the selected transistor. In the description, in addition to the parameters for selection, all the parameters of the transistor from the reference database will be presented. In addition, the following suggested replacement for this transistor and other transistors, the main parameters of which are not worse or slightly better.