November 5, 2010 AT 12:12 am

Part finder Friday! – The 1N4001 blocking diode

Pt 10509

Another classic part for today, the venerable 1N4001 blocking diode. These guys can take up to 1 Amp with a drop of about a volt. We like to use them to protect 7805’s from AC/negative input voltages coming in from a power jack (as a half wave rectifier) or inductive load shunts (for motors, solenoids and relays). They’re not good for signal work, or for boost converters so much as they’re sluggish and leaky. They’re kind of the ‘big galoot’ of diodes: tough, dirt cheap and very handy, so pick some up today using our part finder!

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2 Comments

  1. can someone recommend a surface mount diode that has a very small forward voltage drop.
    it’s to be used to protect the circuit from someone putting the battery in the wrong way.
    i’m using a cr2450 battery and currently using 1n4001 (i think) but the drop is way to much.
    the application is a simple egg timer. it contains just a pic uC a dual 2 segment led and a dual transistor plus some resistors. it’s runs constantly using the ultralow power wakeup feature of the pic.
    thanks
    P

  2. @peter
    Have you considered using a MOSFET?
    http://www.geofex.com/article_folders/mosswitch/mosswitch.htm

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