Vehicular 5V Power Supply There are two parts lists for the circuit. Depending on the current draw of your project, you can select a switching regulator (up to 1000mA output), or a less-expensive linear regulator (up to 400mA). For our VFD-420, the switching regulator is the right choice, since the linear regulator would be operating close to its max output (from a heat-dissipation standpoint). Parts List 1: Switching Supply (1A output) All part numbers refer to Digi-Key (1-800-digikey) · C1,C2--100µF, 50V electrolytic capacitor (part no. P1353-ND) · C3--0.1µF, 50V monolithic ceramic capacitor (part no. P4923-ND) · D1--silicon rectifier diode, 6A, 100V (part no. 6A1MSCT). Note: it's permissible to use a smaller diode, 2A or more. · D2--zener diode, 36V +/-5%, 5W (part no. 1N5365BMSCT) · D3--zener diode, 6V +/-5%, 5W (part no. 1N5340BMSCT) · J1--Auto accessory (cigarette lighter) plug (part no. ZA5073-ND) · R1--50-ohm, 1W resistor (part no. ALSR1F-50-ND) · U1--5V, 1.5A integrated switching regulator (part no. 78ST105HC) · fuse--2A, 250V normal-blow fuse (part no. F119-ND) Parts List 2: Linear Supply (400mA output) · C1,C2--100µF, 50V electrolytic capacitor (part no. P1353-ND) · C3--0.1µF, 50V monolithic ceramic capacitor (part no. P4923-ND) · D1--silicon rectifier diode, 6A, 100V (part no. 6A1MSCT) · D2--zener diode, 36V +/-5%, 5W (part no. 1N5365BMSCT) · D3--zener diode, 6V +/-5%, 5W (part no. 1N5340BMSCT) · J1--Auto accessory (cigarette lighter) plug (part no. ZA5073-ND) · R1--not used · U1--5V, 1.0A linear voltage regulator (part no. NJM7805FA-ND) · Heatsink--aluminum heat sink, bolt to U1 (part no. HS191-ND) · fuse--1A, 250V normal-blow fuse (part no. F115-ND)