# Questions tagged [practical]

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### How do I calculate the transfer function of this basic terminated RC filter?

I'm reading through an electronics book to teach myself, and I'm in the section about filters. I've been following along so far, but now I'm confused about how the author came to a conclusion in his ...
• 13
102 views

### Why do people learn electronics? Need some practical examples [closed]

Examples of why one would to learn electronics are: 1) He works (or intend to) as an electrical engineer 2) He likes (or needs to) repair electronic equipment One thing I find it difficult to ...
81 views

### The mean value of phase noise as a stochastic process

What is the mean value of phase noise as a stochastic process? Where can I get a theoretical analysis of this topic?
• 41
336 views

### Bypass LED with switch (why)?

I have a schematic attached that appears to show a switch bypassing an LED, or the other way around. In the working device operating the switch lights the LED and engages (as in turns 'on' a 'normally'...
• 103
968 views

### How to experimentally measure damping in RLC circuits?

I know there are methods to theoretically determine the damping factor and quality factor in RLC circuits. Equations such as $$\zeta = \frac{R_s}{2} \sqrt{\frac{C}{L}}$$ $$Q = \frac{1}{2\zeta}$$ ...
43 views

### What would be involved in rectifying electricity from a faulty car alternator?

Disclaimer: Newbe As I understand things: a car "alternator" generates a/c current the alternator contains diodes that rectify the current to d/c current if one or more diodes fail then the ...
• 105
1 vote
78 views

### Question regarding dielectric breakdown (especially for stun guns)

This question occurred to me after looking at some models of stun guns. What I noticed was that some of them like one I bought had metal extensions sort of like prongs, or like tiny metal cones. I ...
• 479
122 views

### How to measure resistance with a multimeter?

This may be a very simple question. In my lab guide (I am a freshman Electronic Engineering student), we are supposed to build and analyze a circuit on a breadboard. First, we need to select some ...
• 577
754 views

### The effects of Op amp Bias current

This is regarding an integrator op amp design, the rate at which the input voltage charges the integrator's feedback capacitor is 150V/s. I am trying to justify the minimum feedback capacitor value ...
791 views

### Can reverse voltage gain for a BJT be negative?

While observing the input characteristics of a Bipolar Junction Transistor(BC547), I observed from the graph that the reverse voltage gain came out to be negative. Is this possible and if so, what is ...
• 371
1k views

### What is the simplest possible monostable 555 timer circuit?

Say for instance, the goal is to light an incandescent bulb for x amount of seconds (let's say 20). What is the simplest configuration possible? Of course, simple timer circuits aren't rare, and can ...
• 1,009
490 views

### MOSFET Biasing Problems

I am interested in finding Vgs for E-MOSFET for desired Id or/and Vds. Referring to those equations of drain current in saturation region, value of conduction parameter "K" would be nice to have but ...
• 2,310
1k views

### Time delayed deactivation of a circuit

In a simple electronic circuit with a momentary switched LED (or bulb, tube etc.); what can be done to trigger the LED for several seconds before proceeding to break the circuit? In other words; I ...
• 1,009
172 views

### When to treat transformers as non-ideal?

For an experiment I need to sum a DC and AC Potential. My solution to this was to construct the following circuit: simulate this circuit – Schematic created using CircuitLab Testing this ...
• 51
14k views

### Difference between an ideal integrator and a practical one

I only learned about the ideal integrator design (top circuit), but when I searched for a practical model for an integrator I found it was like the one in the bottom circuit. Two new elements, Rf and ...
• 105
177 views

### Finding the resistance of a practical inductor having its reactive power

Suppose I have a simple practical inductor as such: simulate this circuit – Schematic created using CircuitLab L is known. R is unknown and we need to find it. The supply frequency (say $f$) ...
• 145
199 views

### Get practial resistances for the Current Divider [closed]

My understanding The resistance as seen through the load is just Rs, Therefore 60K < Rs < 80K. Is (current Through Rs Resistance) IL (current through RL load)...
• 103
552 views

### What happens if I put my DC voltage source AFTER the diode instead of before?

I have a homework question on diodes, in which I have to calculate the Voltages across the diodes. All the questions I have encountered thus far have had the DC source BEFORE the diode. This one has ...
• 179
610 views

### Why isn't Ohm's law working for this simple circuit?

I have a 70W 12V-500V DC power converter, and something in these pictures is not adding up. I run the 500V output through a high-voltage 332kΩ resistor. Now, using the left multimeter I ...
• 2,252
2k views

### Amateur question: how circuit analysis methods are applied in "complicated" circuits?

This will sound maybe stupid, but I'm amateur in electronics and I'm in process of learning. I have previously analysed some basic circuits involving opamps, diodes etc. Although some circuit looks ...
• 225
397 views

### practical concideration for op-amp differential amplifier

i'm trying to make a current sensor based on an op-amp differential amplifier with a unity gain (all resistors are equal so to have the best CMRR.) The output of the op-amp differential amplifier ...
555 views

### Transistor active mode

I have been looking on the web but all I found was theory that I couldn't fully understand,nor apply .How can a NPN transistor be switched on in active mode?I would appreciate if you would give a more ...
• 1,358
456 views

### Op Amp high voltage output

Is it possible to output voltages in the range of kilovolts and current of atleast >1mA using an input of <10V on a consumer electronics op amp such as IC 741? If not, then why?
• 297
1k views

### Can I obtain a new voltage source from outputs of two cascaded linear voltage regulators in practice?

I have a device which works with 7V. I have a 7812 and 7805 already running in the circuit. Can I use the outputs of this voltage regulators to feed the 7V device? I know this is possible in theory. ...
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720 views

### Why do they place a high current device in a low current package?

For instance, it is said that the practical current limit of the TO-220 device is 75A. But I frequently see MOSFET devices for which the specified maximum continuous drain current is above 75A. (...
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538 views

### Why use only oversimplified/ideal equivalent circuits?

Most circuit analysis books use ideal resistor, inductor, capacitor and don't even bother to show practical circuits of these components, let alone any solved examples with practical circuits. For ...
• 179
489 views

### Practice for complex electronic circuits [closed]

I'm self-learning electronics; I've watched Anant Agarwal videos and read his book and another book "Electronic Devices And Circuit Theory- Robert L. Boylestad". But, now, I need to practice more on ...
1 vote
3k views

### Is it practically okay to use darlington triple?

I need to control a very high current in my project. I'm planning to use darlington formation with three transistors. I'm planning to use BQ24450 to charge a group of 12V acid-lead battery. BQ24450 ...
• 13.5k
1 vote
2k views

### Increasing precision of a practical opamp circuit when the input signal is very small

I have a sensor which outputs a normally distributed baseband signal with cut-off frequency of 100Hz, whose mean is ~1mV and variance is (0.1mV)2. I want to amplify it about x1000 times by using TL084 ...
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853 views

### Practical designs/practices for home electronics

I need an automatic voltage stabilizer. I'm thinking about building my own. I've searched the internet and consulted several books. The diagrams in books show only the bare bones, basic design that ...
1k views

### How should I write a feasibility study report?

I may be called upon to write a feasibility study report for consumer hardware (to be manufactured) and/or a service to be offered to clients in the near term. What is the proper technique here? ...
• 1,149
7k views

### MIMO: How Can Two Antennas So Close Together Receive Different Signals?

I'm trying to understand how MIMO (as used by 802.11n wi-fi and some upcoming cellular data standards) works in practice. I understand at least the gist of the theory of spatial multiplexing. What I ...
• 207
823 views

### Transfer Function of Non-Ideal Transformer

What is the mathematical relationship between primary and secondary windings? It can be either in the s-domain, or a time domain expression. This expression must contain all realistic parameters, ...
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13k views

### Sample Application with LHI 778 PIR Sensor

For a motion detecting application I found a sensor with code LHI 778. If you look at the datasheet in the link, the characteristics of its internal FET transistor is not specified and there is no ...
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