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Is open for sales again? Dan's Small Parts and Kits (danssmallpartsandkits.net) Always one of my favorite vendors for leaded parts. Win W5JAG

I tried a simple experiment. I looked up a tutorial on class A amplifier design at this link: https://www.electronics-tutorials.ws/amplifier/class-ab-amplifier.html I also downloaded the datasheet for a 2N3904 Transistor. I first informed ChatGPT that I would paste the tutorial and the datasheet into the chat. Then, I asked it for the component values to make an audio preamp using a 2N3904 transistor. It read the article, learned what to do, and then did the math based on the datasheet. You can then ask more questions, like changing the gain and impedance. Even if not perfect, it was really cool to do and a nice jumping-off point. Here is the Response: ====================================================================================== For an audio preamp with a 20 Hz to 20 kHz frequency response and a 600 ohm output impedance, we can make some more precise component value selections to achieve a suitable design. Additionally, assuming a high impedance input, we can target a voltage gain of around 10 (20 dB) for this example. Keep in mind that specific design requirements and preferences may lead to different component values. Component Values: 1. Transistor: 2N3904 (Silicon NPN transistor, as provided in the data). 2. Input Coupling Capacitor (C1): To achieve a 20 Hz to 20 kHz frequency response, a capacitor with a lower cutoff frequency should be used. Let's choose C1 ≈ 4.7µF. 3. Emitter Resistor (R1): We can set the biasing current for the transistor to a reasonable value, such as Ic ≈ 1 mA. Assuming Vbe ≈ 0.7 V, we can calculate R1 ≈ (Vcc - Vbe) / Ic ≈ (9 V - 0.7 V) / 0.001 A ≈ 8.3kΩ. We can choose a standard resistor value of R1 ≈ 8.2kΩ. 4. Emitter Bypass Capacitor (Ceb): To improve low-frequency response, we can add a bypass capacitor in parallel with R1. Let's use Ceb ≈ 10µF. 5. Collector Load Resistor (R2): To achieve a voltage gain (Av) of 10 (20 dB), we can use the following formula: Av = - R2 / R1. Solving for R2, we get R2 ≈ - Av R1 ≈ - 10 8.2kΩ ≈ - 82kΩ. Since R2 should have a positive value, we can choose R2 ≈ 82kΩ. 6. Output Coupling Capacitor (C2): To allow the AC audio signal to pass through, we can choose C2 ≈ 4.7µF (similar to C1). 7. Load Resistor (R3): To match the 600 ohm output impedance, we can set R3 ≈ 600Ω. Please note that the values above are calculated based on typical design considerations and assumptions. Depending on specific component availability and desired performance, it may be necessary to adjust the values slightly. Additionally, a suitable power supply should be provided to bias the transistor and provide the necessary voltage levels for the preamp circuit. Remember to simulate the circuit and test it before building to ensure that it meets your requirements and provides the desired audio performance. If you have any further questions or need additional assistance, feel free to ask! ====================================================================================== I used the free version of ChatGPT https://chat.openai.com/

Note: It is Important to be cautious of counterfeits. To ensure authenticity, I recommend visiting the official TinySA website at https://www.tinysa.org/wiki/ and checking the "Where to Buy" section located at the top left of the page. This will provide a list of authorized sellers. Personally, I purchased mine from the SeeSii store on Amazon, ensuring a genuine product with reliable support. Introduction: As a hobbyist exploring the realms of electronics and radio, I recently acquired the TinySA spectrum analyzer. This compact device has exceeded my expectations with its impressive capabilities, allowing me to analyze and generate signals across various frequency bands. In this review, I will share my firsthand experience and highlight the features that make the TinySA a must-have tool for any hobbyist. Compact Design and Inputs: One of the standout features of the TinySA is its compact design, which does not compromise on functionality. The device is equipped with two inputs tailored to different frequency ranges. The first input handles MF/HF/VHF signals with exceptional quality, covering an extensive frequency range from 0.1MHz to 350MHz. The second input, designed for UHF signals, performs admirably in the 240MHz to 960MHz range. This versatility allows me to explore a wide spectrum of frequencies and pursue diverse hobbyist projects. Flexible Outputs: Not only does the TinySA serve as a spectrum analyzer, but it also excels as a signal generator. Its two output options provide the flexibility needed for various applications. The sine wave output covers frequencies ranging from 0.1MHz to 350MHz, enabling me to generate smooth, continuous signals. On the other hand, the square wave output, which operates between 240MHz and 960MHz, allows me to experiment with different waveforms. This versatility makes the TinySA an invaluable tool for testing and prototyping electronic circuits. The Ultra Version: For those seeking even more advanced capabilities, the TinySA Ultra version is available and has even more impressive features. With its larger 4-inch screen, the Ultra version expands the spectrum analyzer's capabilities. It can operate within the 0.1MHz to 800MHz range, allowing for comprehensive signal analysis. Enabling the Ultra mode further enhances the TinySA Ultra, enabling level calibration up to an astonishing 6GHz. This wide frequency coverage grants you access to signals previously inaccessible with other devices. It can become an indispensable asset for your specialized hobbyist projects. Affordability and Availability: The TinySA's affordability is amazing. I purchased it for just US $67 on sale, prime day, around $85 normally. (plus shipping) from the Amazon Seesii Store. It is also available on other distributors and prices vary widley. It's important to be cautious of counterfeits. To ensure authenticity, I recommend visiting the official TinySA website at https://www.tinysa.org/wiki/ and checking the "Where to Buy" section located at the top left of the page. This will provide a list of authorized sellers. Personally, I purchased mine from the SeeSii store on Amazon, ensuring a genuine product with reliable support. Here is a YouTube video comparing an expensive Rigol Spectrum Anaylizer DSA 815 to the TinySA. Very surprising. https://www.youtube.com/watch?v=q8v_oh28zs0 Learning Resources: Initially, I had concerns about the learning curve associated with the TinySA. However, I was pleasantly surprised to find an abundance of learning resources available. The official TinySA website hosts a comprehensive wiki that includes a detailed manual and an introductory video. These resources provided me with a solid foundation to start using the device effectively. Additionally, YouTube proved to be a treasure trove of instructional videos, showcasing practical demonstrations of the TinySA's features and applications. These resources have empowered me to explore and expand my knowledge in the world of spectrum analysis. Conclusion: Having personally experienced the capabilities of the TinySA spectrum analyzer, I can confidently say that it is a game-changer for hobbyists and radio enthusiasts. Its compact design, versatile inputs, flexible outputs, and advanced Ultra version make it an essential tool for any electronic exploration. The TinySA's affordable price, combined with its remarkable performance, makes it a worthwhile investment. By ensuring authenticity through authorized sellers, such as the SeeSii store on Amazon, hobbyists can acquire a genuine TinySA with reliable support. Embrace the power of the TinySA, and open the doors to endless possibilities in your hobbyist endeavors. Sources: 1. tinySA | Main / HomePage. https://www.tinysa.org/wiki/. 2. tinySA Ultra Reviews: A 0.1 MHz – 6 GHz Spectrum Analyzer for $120. https://www.rtl-sdr.com/tinysa-ultra-reviews-a-0-1-mhz-6-ghz-spectrum-analyzer-for-120/. 3. Hugen Launches Portable TinySA Spectrum Analyser. https://www.electronics-lab.com/hugen-launches-portable-tinysa-spectrum-analyser/. Here is a YouTube video comparing an expensive Rigol Spectrum Anaylizer DSA 815 to the TinySA. Very surprising.https://www.youtube.com/watch?v=q8v_oh28zs0