Drive 9Vdc buzzer from 120Vac without using a transformer (no room)

Discussion in 'The Projects Forum' started by JJHH123, Dec 31, 2015.

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  1. JJHH123

    Thread Starter New Member

    Dec 31, 2015
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    Hi,

    I have a protection circuit that needs to alarm when a fuse blows. The alarm needs to be a 9vdc 105db 8mA buzzer that is driven from a 120Vac power supply. I have no other load on this portion of the circuit. I do not have any room for a small transformer. Is this possible to do?? I have room for a full bridge rectifier to get my dc. How can I step down the voltage from 120 to 9 and for heat dispensing is it better to step down in ac or dc?
    Thanks for any help.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    What you are asking is prohibited on this forum:

    Restricted topics. The following topics are regularly raised however are considered "off-topic" at all times and will result in Your thread being closed without question:

    • Any kind of over-unity devices and systems
    • Devices designed to electrocute or shock another person
    • LEDs to mains
    • Phone jammers
    • Rail guns and high-energy projectile devices
    • Transformer-less power supplies
    If You come across a thread or post discussing any of the above topics please report the thread so We can close, and if necessary remove, the offending thread/posts.

    Bertus
     
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