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1 amp current at 14 volts causes a .9 volt drop across a switch. what is the resistance at the switch?
Wiki User
∙ 14y ago
V = I*R
If you solved this for resistance, this means you would have:
V/I = R
You set V = .9 volts, I = 1 amp, and solve to get .9 Ohms.
Wiki User
∙ 14y ago
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Can Crystal Diode acts as a Automatic Switch?
A diode typically has low resistance for current in one direction, and high resistance for current in the other direction. This is not really the description of anything that could be called a 'switch'.
A switch is connected in a series with a 75-W bulb to a source of 120V. what is the potential difference across the switch when it is closed?
If the switch, light bulb, and source are all connected in series and the switch is ideal (has no resistance), then the switch acts as a short. There is no potential difference across the short.
How does pn junction diode can be used as an electronic switch?
A diode allows current to flow in only one direction. If the current is flowing, the diode has a low resistance and it behaves like a wire or a switch in the on position. If the voltage across the diode is reversed, no current flows and the diode has a very high resistance. It behaves like a switch in the off position. DC voltages are used to switch the diode on or off. The signal that is being switched is usually an AC audio or radio signal. Capacitors block DC but pass AC signals. By combining diodes and capacitors, the AC and DC signals are kept separate and the switch can be built.
How does a switch control an electric device?
A switch basically represents a gap in the electric circuit. Electric current can pass through a circuit only if it is complete. An incomplete circuit can never pass a current through it. When the switch is in the 'off' position, the circuit has a break (gap) in it. When you put the switch in 'on' position, the circuit wire join and the circuit gets completed.
When measuring voltage drop across a switch what is the maximum allowable voltage drop?
The voltage drop should be as close to zero as would be readable by a typical volt meter. If it is measurable you likely have a problem with corrosion or oxidation in switch that is increasing resistance. If you can measure a voltage drop across a closed switch contact, replace the switch. Or the switch is open, try flipping the switch!
What is the maximum resistance you want to see across a switch?
The maximum resistance across a switch should be infinite.
What is the voltage across the load R when the switch is ON?
It's the product of the resistance of that resistive load and the current passing through it.
What voltage would you expect to measure across closed switch?
Original Correct Answer:The voltage across an open switch should equal the supply voltage.More Detailed Answer:The above answer is basically correct. However, it may not be EXACTLY the supply voltage.This is counter-intuitive at first glance and confuses a lot of people, including electrical engineers. The reason is this. Voltage, Current and Resistance are all interrelated by Ohms Law. Voltage equals Current multiplied by Resistance.It is easy to think that since a switch is open, then you do not have current flow through the circuit. Thus, current times any Resistance is equal to zero volts because the current is equal to zero. Thus, by this logic, you would expect to find zero volts across the switch. In actuality this is true.But, when you insert you meter, you change the conditions of the circuit, and the following is the result.Let's say that you have a circuit with a resistance load like a heater, and a inductive load like a motor. The switch that powers these devices is open, thus their is no current flowing through the resistance or inductive loads.Now you put the meter across the open switch. When you do, you insert a very large resistance in parallel to the open switch. Why? Because to get volts, the meter measures current flow through a known resistance, and then calculates voltage. To keep the resistance from impacting the circuit performance, the resistance is very large. Therefore, when you insert the meter, you will get a flow of current through the meter.Because of this large resistance, the current trough the resistance load, inductive load, and wires is very small. Thus, the voltage drop across the loads and wiring is very small. Therefore, it appears that the entire voltage in the circuit is across the huge resistance in the meter. The result is a voltage reading that is very near the source voltage.Let's do the math. Let's assume you have 120 volts. You also have a resistance of 500 ohms, and a motor winding that has 0 ohms resistance when DC is applied (This is true for motors). The meter has a 10 million ohm resistance.If these loads are in series, the total resistance is 10Million 500 ohms. The 11.9 microamps. By multiplying the current flow to each resistance, you get 6 millivolts across the resistance, no voltage across the motor winding, and 119.994 across the open switch or meter. Since a meter rounds it reading, you would get 120.If the loads are in parellel, you would get the same thing, becuase the switch is in series with both loads. In this example, the motor winding would have all the current flow through it since it is zero ohms, and the parallel resitance load is 500 ohms. Thus, the total resistance is the 10 million of the meter, and this resistance drive the current, and thus the largest voltage drop is at the swtich/meter. You could decide to remove the motor from this parellel circuit. If you did then the then the result is the series circuit above.
Can Crystal Diode acts as a Automatic Switch?
A diode typically has low resistance for current in one direction, and high resistance for current in the other direction. This is not really the description of anything that could be called a 'switch'.
Why does more current flow through the bulb when the reed switch was replaced with copper wire?
Copper wire has apparently lower resistance than the reed switch. The lower electric resistance, the higher electric current.
Will an open switch record a resistance of zero ohms?
no...... ideal open switch should have a resistance of infinity... the question should be a closed switch http://wiki.answers.com/Q/Will_an_open_switch_record_a_resistance_of_zero_ohms" but this is also false because any good conductor will have a small resistance the connecting wire resistance is exhibitted across the terminals of the switch
What are the reason for the inclusion of the 1kΩ resistance in diode circuit?
To limit current flow. the diode is effectively a switch with a small voltage drop across it (usually in the range of .5 - .8 volts). If you hook up a 1 volt battery to this, and follow ohms law: I = (1 - .8)/(resistance, which is zero) = .2 / 0 = a big amount of current (current will be limited by the source resistance, but this current is probably sufficient to damage the diode anyway).
Would you show me a diagram of a series circuit?
Diagrams are not supported with WikiAnswers, sorry, so you will have to use your imagination...A simple series circuit can be built with a battery, a switch, and a light bulb. One end of the battery is connected to one end of the switch. The other end of the switch is connected to one end of the bulb. The other end of the bulb is connected to the other end of the battery.If the switch is open, no current flows, and the bulb does not illuminate. If the switch is closed, current flows, and the bulb illuminates. By Ohm's law, the current through the bulb is proportional to the battery voltage and inversely proportional to the resistance of the bulb. Note, of course, that we are talking about hot resistance of the bulb, because cold resistance is an entirely different thing, due to the temperature coefficient of the bulb. Also, by Kirchoff's current law, the current at every point in this simple series circuit is the same and, by Kirchoff's voltage law, the voltage across the battery is the same as the voltage across the bulb.
What is an example of Ohms Law?
The simplest example of Ohm's Law is an old fashioned dimmer switch in your house. As you turn the dimmer switch up, the light gradually brightens until it reaches full intensity. Conversely, you can turn the dimmer switch down, and the light gradually darkens.The dimmer switch is a variable resistor. That is, the electrical resistance of the dimmer switch changes as you rotate the knob. Ohm's Law tells us that the flow of current is directly proportional to the voltage, and inversely proportional to the resistance. Since the voltage across the switch doesn't change, the only thing that changes is the resistance when you turn the dimmer switch knob.As you turn the dimmer switch down, you are actually increasing the resistance of the dimmer switch. The current is inversely proportional to the resistance, so as the resistance goes up, the current (flow of electricity) goes down, and the light gets darker. This is an example of Ohm's Law.NOTE: This example applies to rheostat switches, and does not apply to modern current-clipping dimmer switches. Rheostat switches are seldom used now because they can overheat, but the illustration is still a useful example of Ohm's Law.
A switch is connected in a series with a 75-W bulb to a source of 120V. what is the potential difference across the switch when it is closed?
If the switch, light bulb, and source are all connected in series and the switch is ideal (has no resistance), then the switch acts as a short. There is no potential difference across the short.
What should be the current rating of a 120VDC 0.4A temperature switch at 24 V DC?
0.4A. The power dissipated in the switch and therefore how hot it gets depends on the current and the resistance.
Why does more current flow through copper wire than a reed switch?
Ideally the reed switch should be able pass as much current as the wire supplying it. A voltage drop across the switch would indicate resistance and suggest that the maximum rated current has been exceeded. Reed switches are delicate and should only switch small currents. They are used where actuation by a magnet is required, without mechanical interference. To switch larger currents a relay should be used, fed from the reed.
