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8 votes
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Maximum DC power available over specific distances from source

I'm working on a small LVDC project using 60VDC to distribute power over varying distances OK, 60 volts is the input voltage. The voltage drop with this current can be calculated to be approx. 30V ...
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6 votes

Relation between collector current and Vce voltage in saturation mode

Interesting question. I try my 2 cents on the matter, it's just a guess, don't take me seriously. In a BJT, saturation voltage \$V_{CE}\$ depends on many factors, the two most important being the ...
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6 votes
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Relation between collector current and Vce voltage in saturation mode

As I was surprised by a picture as the first of OP, I tried to find it by simulation. No too easy, as we "do not know" how it was obtained and what is the signification of beta=10. I guess ...
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Relation between collector current and Vce voltage in saturation mode

Almost :) The C-E voltage is lowest at the collector current around 5mA. It increases whether you decrease or increase the current away from this saddle point.
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4 votes

Maximum DC power available over specific distances from source

As your math indicates, for a given resistance of cable maximum power is transferred when volt drop in the cable is equal to half the supply voltage. However given your goal is to supply network ...
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3 votes
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Control AC load via relay with DC trigger?

Use a DC relay for this with enough current rating for the lamp, like those used in cars. The trigger source defines the coil, not the load.
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3 votes
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Design calculations for LVDC grid

You are powering a 12V load with some nominal current, through a DC/DC converter. The DC/DC converter will maintain its output at 12V no matter what, and deliver the current demanded by the load. Let'...
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3 votes
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What is the current across the resistor given in the figure?

If you assume the 3A current flows across the short, then the voltage across the 30Ohm resistor is 0V and since the current source is ideal, it can have any voltage across it (even 0V), hence the ...
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Difference between application of series and parallel (grounded) capacitor

As you correctly surmise, C1 and C2 are there to block DC on the input and output sides respectively. L2 and L3 form the "top halves" of voltage dividers, where the "bottom halves" ...
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3 votes

Difference between application of series and parallel (grounded) capacitor

So what you ask must be thought with the context that it is an RF device, such as RF amplifier. Yes, the capacitor in series is used to block DC and pass RF only. This lets the chip input to bias ...
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2 votes

Control AC load via relay with DC trigger?

Standard 12 V DC automotive relays would do. Two would be required, one to switch on the headlight and the other to select 'high' or 'low' beam.
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2 votes

Relation between collector current and Vce voltage in saturation mode

Can I say when collector current increases voltage Vce also increases in saturation mode? Yes, you can - assuming no other variables are changed. However you might be a little confused by the ...
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2 votes

How to buy high-speed 220 VAC - 5 VAC transformer

A "high frequency" transformer in a switching converter would be acting as the switching inductance. These having high frequency DC currents (via rectifier) switched through them and are ...
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1 vote

How to determine the most efficient voltage transformation?

It depends on the efficiency of the converter itself. The formula would be efficiency=(power out)/(power in). Simple enough. Two supplies with similar efficiency ratings will indeed have the same ...
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What value of resistor is needed to limit current to 0.5 ampere in a 12V DC circuit?

It's generally a bad idea to add a series resistor to a DC motor because it will reduce the torque without reducing the no-load speed at all. It might be acceptable for certain types of loads such as ...
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Select PSU for 12V DC water pump

What about "headroom"? Let's assume something blocks the motor. Centrifugal pumps often experience reduced torque when the inlet or output is blocked. so electrically that may not be a ...
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1 vote

Select PSU for 12V DC water pump

If you use a power supply to it's maximum rating, it will always reach it's maximum rated temperature. Pumps demand at least 5x the rated power on startup, often 10x so lower voltage is expected ...
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1 vote
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Heat Problem with MOSFET Controlling a DC Shunt Motor

I figured it out. The motor I was trying to use was just broken. I connected it to a different motor, and the setup works just fine. Thanks to the people that tried to help, and sorry for the fake ...
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1 vote
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Optimizing Peltier water cooler set up

The circulation speed vs. heat removal rate has an asymmetric knee. With circulation too slow, the tank will heat faster than the slowly flowing very cold water can absorb. Go slow enough, and ...
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1 vote

Controlling 0-5V from 0-3.3V PWM pin and 5V power

Use PWM. Connect the transistor in a common emitter configuration, with emitter connected to ground, base connected via a 4k7 resistor to GPIO, and collector collected to the cathode (-) of the LED ...
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1 vote

Integrator as DC servo

Yes, it does correct for the voltage across R2 due to bias current. The integrator continues to integrate until the voltage at inverting input is 0V (or Vcc/2) in a single-supply circuit. And Yes, I ...
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1 vote
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Integrator as DC servo

I sense the offset of the wideband amplifier (WBA) at its inverting input, where Vos resides without any dependence on Vin. I used am integrator and lowpass-filter (LPF) only to limit the noise of the ...
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