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HarryA
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Posts posted by HarryA
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It is back. On first loading this site I see: members 94524 and 1 reply for this topic. On refreshing see members 94526 and replies 2.
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That works . I see the number of members at 94,524 before and after refreshing at the browser.
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I noticed that Firefox was caching this site. For example coming here today I see member a count of 94,515. If I force the browster to refresh I get a count of 94,520. I have dorked around with the Firefox browser to find how or where it was caching the site; to no avail. I tried Opera and Edge browsers and got the same results - old data/web site 94,515. It must be cached upon a the server somewhere?
I have not noticed this with other web sites but perhaps other web sites are cached but I do not notice.
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Conduction loss is larges loss in a MOSFET, it occurs when the MOSFET is in the 'on' state and current flows through its channel. It's calculated using the formula:
P = Current^2 × Rds. Also switching losses occur during switch the transistor on and off.Look it this calculator and you will see how large conduction losses are compared to the other losses. https://www.dmcinfo.com/latest-thinking/blog/id/10517/mosfet-power-loss-calculatorThe LTspice circuit simulator has a large number of MOSFETs listed. If you post what voltages and currents you are interested in I could see what is listed there. It would benefit you to learn to use the simulator for your work. -
How do you transfer data from the buffer to a USB interface?
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Can you pick a signal off the speakers? Perhaps use a three wire connector-jack that disconnects the speakers when you plug it in.
The grounds at the speakers are required by the simulator.
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You would need to supply a schematic for anyone to help you.
What is "2008"?
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I2C is for data transmission not for audio.
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One would expect the heads to be parked (off the platters) if not actively in use.
If it still works then it must be okay?
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Given two gaps in series both gaps would have to fire simultaneously. Say the narrow gap fired first; where would the electrons come from?
On 11/13/2024 at 7:18 PM, russwr said:but that is always in microseconds, not regular needed milliseconds.
What do you mean by not regular needed milliseconds?
I built a CDI for a chainsaw. At 1800 rpm it worked fine, at 3600 rpm it would blow the 10 ampere fuse in the 12v to 350v up-converter. I solved the problem by buying a new chainsaw 😉
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The TLV9002 output at 25C is 67.8 mv; to get 4v one would need an amplifier gain of 58.99
At 50C the output is 3.27v ; to get 12 volts one would a gain of 3.66
I think a log amplifier would work here.
"Log amps are non-linear, analog amplifiers that produce an output that is the logarithm of the input signal or the signal’s envelope. They compress input signals having a large dynamic range into output signals with a fixed amplitude range. This is accomplished by providing high gain for low input signal levels and progressively lower gain for higher level signals"
The LTspice simulator has one Analog Devices log amplifier in it. I could try to simulator a circuit using a ramp of 67.8mv to 3.27 As Analog Devices has numerous log amplifier chips and they own the the LTspice simulator it seems odd there would not be more.
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Perhaps you will something useful from these two circuits; although somewhat dated.
If you are interested I will try to redo the second later.
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There is some good information on using Arduino boards and Bluetooth in the Arduino Cookbook. It can be download free from;
Cookbook One can use a Bluetooth enabled PC for testing I believe. The pairing address from the table saw would be needed I gather.
The Arduino board to the vacuum cleaner can be done with a simple transistor circuit driving a relay as an on/off switch.
If you need further help do not be afraid to ask.
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I will message you a temp email address. You could try sending me an email with your LTspice .asc file as an attachment. I could play with it. If I can figure how to do messaging.
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Try this. On your schematic window click on a blank area. Select Edit Simulation CMD then in the popup dialog box select AC Analysis. Select Linear or Decade(?) . Then I used: 500, 30k, 50k. Next click on the signal symbol and set then AC voltage to some value. On running the simulation I got a peak at 39.36k.
Your schematic is further along then mine so you should get different results. I used the 53000u for the capacitor.
This guy uses a different approach but I can not follow him
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I think you would find this free Power Electronics course from MIT very helpful. The math is not to bad 😉
I find it very interesting. There are 38 lectures in all; by the end you have a good understanding of power circuits.
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I think the post is worth reading. So lets try Google translator:
First, microcontroller I/O ports have limited load capability, typically allowing about 10-20 mA of current. Therefore, they are not usually used to drive loads directly.First, microcontroller I/O ports have limited load capability, typically allowing about 10-20 mA of current. Therefore, they are not usually used to drive loads directly.
https://youtu.be/pbz5aMdxSEU First, microcontroller I/O ports have limited load capability, usually allowing about 10-20 mA of current. Therefore, they are not usually used to drive loads directly. image.png.4e399c62899257b83f0e2103daa204e1.png Let's briefly compare the differences in driving BJTs and MOSFETs. Bipolar Junction Transistor (BJT): BJTs are current-controlled devices. As long as the base-emitter voltage (Ube) exceeds the threshold voltage (usually 0.7V), the transistor will turn on. For BJTs, 3.3V is definitely greater than Ube, and the base current (Ib) can be calculated as \( Ib = \frac{(VO - 0.7V)}{R2} \). By connecting an appropriate resistor in series with the base, the BJT can be operated in saturation. Microcontrollers are usually targeted for low power consumption, so the supply voltage is usually low, around 3.3V.
MOSFET:
MOSFET is a voltage controlled device. The gate-source voltage (Vgs) must exceed the threshold voltage to turn on, which is generally around 3-5V, and the saturation drive voltage is 6-8V, which is higher than the 3.3V of the I/O port. If driven with 3.3V, the MOSFET may not be fully turned on or operate in a partially turned-on state. In this state, the MOSFET has a high internal resistance, which limits its ability to handle high current loads, resulting in increased power dissipation and potential damage.
Therefore, it is usually better to use a microcontroller to control the BJT, which in turn drives the MOSFET. Why use a BJT to drive a MOSFET? This is because BJTs have lower load capabilities compared to MOSFETs, making them suitable for control applications. Can MOSFETs be driven directly? While it is possible with some low power MOSFETs, it is generally not recommended for larger loads. -
I once had an amplifier that played music with no inputs. It turned out that it was a local am radio station; the results of poor grounding. If you have a wee soldering iron try resoldering the ground on the TL082 op amp. Perhaps that will help.
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The results from the LTspice simulation. Beware that sometimes the simulators lie.
In the first plots the the red line is the voltage across capacitor c1. The green line is the voltage at the mosfet drain. The voltages peaks at 1.34 kv in 24 seconds. The green plot is solid as it is maded up of pulses. The breaks in the red plot are do to the scaling in the Gimp image processing software.
In the next three plots; the white plot is the input to the mosfet. 6v peak, 50hz, 20ms high and 20 ms low. The red plot is the current from the mosfet; at 0.905 amperes. While the green plot is the current through one of the coils at 0.301 amperes.
Attach is the circuit as used in the simulation. Using components close to the original circuit that the simulator has.
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I put that circuit into the LTspice circuit simulator but the simulator is not happy with it. I will try later to get it to work. The simulator would give insight into what the currents look like.
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"After swapping the terminals to the preamp, the hum moved to the other channel."
Would not this suggest the problem is in the preamp?
Question storage elecronic devices and aluminum electrolytic capacitor
in Power Electronics
Posted
see:
https://antiqueradios.com/forums/viewtopic.php?t=444008
https://www.electro-tech-online.com/threads/question-capacitors-storage.167038/