The PB-501 is a low-cost logic trainer designed to make efficient use of laboratory time for students of digital electronics. It features a built-in 1 KHz user-variable clock, two debounced logic pulsers, eight dual-function logic switches, and eight LED logic indicators. The unit includes a permanent UBS-100 solderless breadboarding socket with 840 tie points, providing ample space for building circuits with up to eight 14-pin DIP ICs. Power is supplied by four "C" batteries or an optional 6 VDC adapter. Housed in a tough molded plastic carrying case, the PB-501 is a complete solution for designing and experimenting with logic circuitry in an educational setting.