I'm planning to operate a 15mm piezo disc as a buzzer at about 5 KHz. Can I use a 5mH 0.5W axial inductor for this? Peak current through the inductor is 70 mA, average current 22 mA, average dissipation is 2.3 mW (as per LTspice; with 1 Ohm resistance, I don't know actual resistance of inductor).

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The inductors look something like these... https://i.stack.imgur.com/we1zc.jpg

update: This is the one I'm considering https://www.ebay.com/itm/50PCS-0410-Color-Ring-Inductance-4-7MH-472K-1-2W-Axial-RF-Choke-Coil-Inductor/351831546222 And a related datasheet https://www.taitroncomponents.com/catalog/Datasheet/TIA0204.pdf lists 85mA max and 20 ohms for the 1mH inductor.

Found another one http://www.mantech.co.za/Datasheets/Products/ECXX_3L.pdf This one says 30 ohms, Isat 120mA, Irms-max 100mA for 4.7mH inductor.

So, I should be safe, right (and can maybe get rid of the additional 20 ohm resistor I have)?

  • \$\begingroup\$ What is the rated saturation current of the inductor? \$\endgroup\$ – Spehro Pefhany Nov 16 '18 at 19:12
  • \$\begingroup\$ I have no idea... yet. Just made an update to the post. \$\endgroup\$ – Indraneel Nov 16 '18 at 19:21
  • \$\begingroup\$ Saturation current may be just over 100mA, from what I understand from unrelated datasheets. \$\endgroup\$ – Indraneel Nov 16 '18 at 19:27
  • \$\begingroup\$ What is the diode for? \$\endgroup\$ – Edgar Brown Nov 16 '18 at 20:21
  • \$\begingroup\$ @EdgarBrown I'm getting a negative voltage (<-15V) at the collector if the inductor resistance is low. The diode is also helping me get a nice square wave at the collector. I don't understand why either of those are happening, or their implications. \$\endgroup\$ – Indraneel Nov 16 '18 at 20:35

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