• powersup

    From LU9DCE@21:5/101 to BBSRT on Mon Jul 1 18:40:04 2019
    BUILDING A 12 VOLT POWER SUPPLY

    Components:
    ----------

    120 v MOV
    T1 18 volt @ 2 amp. transformer (Radio Shack # 273-1515)
    BR1 Bridge rectifier, 4 Amp. @ 50 PIV (Radio Shack # 276-1146)
    C1 4700 µF @ 35 v. electrolytic capacitor (Radio Shack # 272-1022)
    C2 1000 µF @ 25 v. electrolytic capacitor (Radio Shack # 272-1019)
    C3 .1 µF @ 25 v. disc ceramic capacitor (Radio Shack # 272-135)
    7812 voltage regulator (Radio Shack # 276-1660 assortment) 120 volt, 1 amp. fuse
    3-wire line cord
    sw DPST toggle switch
    Jacks and connectors
    Perf board or project board
    Enclosure

    ┌───────────┐
    │ │ 7812 12-volt VOLTAGE REGULATOR
    └──┐ ° ┌──┘
    ┌──┘ └──┐
    │ │
    └┬─────────┬┘
    │ │
    │ 7812 │ front view
    │ │
    │ │ Pin 1 = input
    └┬┬──┬┬─┬┬┘ Pin 3 = ground
    ││ ││ ││ Pin 2 = output
    ││ ││ ││
    ││ ││ ││
    ││ ││ ││
    └┘ └┘ └┘
    1 3 2




    ┌───────────────────┐
    │ FULL WAVE │
    │ Bridge Rectifier │ BR1
    │ │
    │+ AC -│
    └╥─────╥─────╥─────╥┘
    ║ ║ ║ ║
    ║ ║ ║ ║
    ║ ║ ║ ║
    ║ ║ ║ ║
    ╨ ╨ ╨ ╨







    12-volt Power Supply schematic


    sw fuse T1
    AC __/──┬─▒▒─┐ ac + 1┌──────┐2
    │ )││(─┬─────────┬────┬─────┤ 7812 ├─────┬───────┬──────■+12v out grn ┌──┴──┐ )││( │ bridge │ │ └───┬──┘ │ │
    ---┐ │ mov │ )││( │rectifier│ ─┴─+ 3│ ─┴─+ ─┴─+
    ≡ └──┬──┘ )││( │ │ ─┬─ C1 │ ─┬─ C2 ─┬─ C3
    │ )││( │ BR1 │ │ │ │ │
    AC __/──┴─────)││(─┴─────────┤- │ │ │ │
    sw ac └────┼─────────┴────────┴───────┴─────┐
    ≡ ≡ gnd




    --- Mystic BBS v1.12 A43 (Linux/32)
    * Origin: HAMRADIO telnet lu9dce.dynu.com (21:5/101)