Thanks again for the insights.Īh, but for just $1.65, a 100uF, 10V ceramic capacitor can be yours in single quantities. The capacitive-coupled circuit certainly also has appeal thanks to the grounded output and costs only marginally more to implement. With the right voltage divider on the secondary and so on, the first circuit is appealing because of its proven performance in past board iterations. I wager you'd have to be more knowledgable about the topic than I presently am.Īnyhow, which circuit to go with is a good question at the end of the day is a good question. People apparently use Aluminum electrolytic capacitors in this type of circuit, what I wonder is what the reverse bias would do to it over time. I must be missing something because the ESR of the types of caps I usually consider only add another Ohm or two per their spec sheet.Īs far as capacitor types go, are there preferences one should follow? I was thinking of going with a 100uF 10V ceramic cap as there are no issues with reverse bias then and the cost is only a dollar more vs. Thing is, when I plug in the above formulas, I get a reactance of 26 not 60 Ohms as expected with a 100uF cap 60Hz. That I got my X c reactance wrong is just typical of me, it's been a while since I took my last EE course. I thought I'd explore the capacitive-coupled circuit topology because it's allegedly better at protecting the Atmel. Even though the combined resistance of the two resistors on the secondary of the transformer were very close to the total resistance of the bias circuit, the circuit works. The resistors I used on the secondaries were 100 Ohm (whose output fed into the Arduino) and 2.2k for most of the voltage drop. What is interesting in the light of Grumpy_Mikes earlier comments is that the previous voltage divider on the secondary side was fed by a nominal 6VAC rms wall wart, whose unloaded output was closer to 7.2VAC rms. The previously posted circuit topology has worked for me in the past - I just got my resistor value ratios wrong in my haste to post here. Alternatively, I think your previous circuit was OK, because the capacitor from pin 5 of the transformer to ground means that one end of the transformer secondary is virtually grounded anyway.īoth of you, thanks for the suggestions and formulas. If you want to stick with that circuit, I suggest you increase the two 1K resistors to 22K each and increase the capacitor to 100uF (impedance about 60 ohms 60Hz). Version 1.12.2 improves subcircuits and contains all the new features and bug fixes from the big 1.The 27nF capacitor is way too small, its impedance at 60Hz is around 100K ohms. No matter your skill set, you'll be playing with circuits in no time with iCircuit. You can also create sub circuits to introduce new elements and componentize your designs. Antenna with simulated AM and FM signals. Audio simulation with Speakers, Microphones, Buzzers, and LEDs.LEDs, Diodes, BJ Transistors, and MOSFETs, Thermistors.Manual SPST/SPDT and DPST/DPDT Switches, Push buttons, and Relays.Signal generators, Voltage sources, Current sources, and Dependent sources.Programmable PIC controllers using assembly language or hex files.Programmable Arduino using a subset of the C programming language.The scope can also display the Fourier transform of any signal so that you can see the performance of filters. The scope can simultaneously track many signals over time and features a touch interface to control the total time displayed and stacked and unstacked modes to easily compare signals. If you want to see how a value changes over time, then you can add values to the built-in oscilloscope. The app features a multimeter that you use to probe around the circuit to instantly read voltages and currents. The app has everything from a programmable Arduino, to simple resistors, to switches, to MOSFETS, to digital gates. There are over 300 elements you can use to build your circuits. Instead, you just play with the circuit as you normally would, with the power on! You do not stop to take a measurement or spend a lot of time configuring reports. It's just like working with the real circuit. You use it as you would any CAD program: you add elements, connect them together, and set their properties.īut iCircuit is unlike other CAD programs because it is always simulating. It is the perfect companion to students, hobbyists, and engineers. Its advanced simulation engine can handle both analog and digital circuits and features realtime always-on analysis. ICircuit is the premier iPad and iPhone app for designing and experimenting with circuits and Arduinos.
0 Comments
Leave a Reply. |