On Tue, 15 Jan 2013 09:59:46 -0800 (PST), you wrote: >Also, is there any need to protect the controller pin from the voltage >spikes? And what about current draw, should I put a resistor because of the >inductor, or can I expect small currents?
No - the small high-value inductors have typically hundreds of ohms of series resistance so no smoke if the transistor turns on continuously the transistor base resistor won't pass enough current to damage the MCU. >> Put a 10-100millihenry Inductor across piezo ( you can get some very >> cheap axial ones), and drive >> withan open collector transistor, Note that disconnecting the piezo will >> produce a high voltage >> that may kill the transistor unless you use a HV transistor like MPSA42,. >> if the piezo is solidly >> connected you can usually use a bog-standard NPN as the piezo will limit >> the voltage. >> Also remember that piezos are sharply resonant so tweaking the frequency >> for loudest output makes a >> big difference, regardless of how you drive them. >> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
