[′yü·nə‚jəŋk·shən tran′zis·tər] (electronics) An n-type bar of semiconductor with a p-type alloy region on one side; connections are made to base contacts at either end of the bar and to the p-region. Abbreviated UJT. Formely known as double-base diode; double-base junction diode.SeeUJTSeeUJT