Browsing by Author "Juola, Jimi"

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  • Guitar loudspeaker impedance replication using an active reactive load
    (2023-08-21) Kokkomäki, Elmeri
     Sähkötekniikan korkeakoulu | Master's thesis
    A vacuum tube guitar amplifier cannot be operated without a load, which is typically a speaker cabinet. The impedance curve characteristics of the load affect the response of the amplifier. Different speaker cabinets have different impedance curves. Silent loads, which have gained popularity in the recent years, typically have one or two selectable impedance curves. Ideally, the impedance curve of any kind of speaker cabinet could be replicated with a single adjustable silent load. In this thesis, the impedance curves of several guitar and bass speaker cabinets were measured in order to find common characteristics and differences. Also, a commercial silent load was reverse engineered and an improved adjustable passive load was developed. Finally, an adjustable active reactive load was developed as a proof of concept, as no active loads exist on the market. The developed active load functioned as intended, but the prototypes were not ideal and would require further development.
  • Prototyping electronics and software for a spectrometer module
    (2017-10-23) Juola, Jimi
     Sähkötekniikan korkeakoulu | Master's thesis
    A spectrometer is a device that measures properties of light at selected wavelengths. In this thesis, electronics and software are prototyped for a Hamamatsu C12880MA spectrometer module. The aim of the thesis was to design a spectrometer that is customizable according to customer's needs. This was met by designing and building a device and a software that interfaces with the spectrometer module, digitizes the measured spectrum, and transfers it to a computer. Software on the computer displays the spectrum and colorimetric values related to it. The capabilities of the device were tested by measuring various reference light sources, and the results showed that, for the most part, the device was working as expected.
  • Teholedien lämmönhallinta mikrokontrollerilla
    (2011) Juola, Jimi
     Sähkötekniikan korkeakoulu | Bachelor's thesis