In the above circuit there are several other resistances that are being ignored for simplicity and because most of them are extremely tiny. However, one of the resistances is significant, and that it the internal resistance of the power supply.
Without the resistor shown in the schematic, the internal resistance of the battery becomes the most significant resistance in the circuit and the voltage measure at D2 would remain near zero when the switch is closed and very near zero when the switch is opened.
If the resistor shown were several thousand ohms or greater, the voltage at D2 would measure close to 5 volts when the switch is closed and zero when the switch is open (however D2 will be subject to picking up any nearby static electricity or strong electromagnetic fields when the switch is open).
To prevent D2 from being subject to spurious noise, resistors are often used between signal points and ground to dampen any such undesired noise. To better imagine how this works, imagine a 100 meg ohmmegohm resistor connected to D2 with the other end hanging out into the air. The unconnected end of the large resistor is acting like an antenna picking up any possible noise in the vicinity. Because the resistor shown in the diagram is so much smaller then the imaginary resistor, the noise will seem to be shorted out to ground in comparison.
In a very real sense, this schematic is telling you to add in a known resistor to ground or suffer from the effects of all the resistors not show; some being very very high resistance and some being nearly non-existent. The devil is in the details when it comes to designing a stable circuit.
In the above circuit there are several other resistances that are being ignored for simplicity and because most of them are extremely tiny. However, one of the resistances is significant, and that it the internal resistance of the power supply.
Without the resistor shown in the schematic, the internal resistance of the battery becomes the most significant resistance in the circuit and the voltage measure at D2 would remain near zero when the switch is closed and very near zero when the switch is opened.
If the resistor shown were several thousand ohms or greater, the voltage at D2 would measure close to 5 volts when the switch is closed and zero when the switch is open (however D2 will be subject to picking up any nearby static electricity or strong electromagnetic fields when the switch is open).
To prevent D2 from being subject to spurious noise, resistors are often used between signal points and ground to dampen any such undesired noise. To better imagine how this works, imagine a 100 meg ohm resistor connected to D2 with the other end hanging out into the air. The unconnected end of the large resistor is acting like an antenna picking up any possible noise in the vicinity. Because the resistor shown in the diagram is so much smaller then the imaginary resistor, the noise will seem to be shorted out to ground in comparison.
In a very real sense, this schematic is telling you to add in a known resistor to ground or suffer from the effects of all the resistors not show; some being very very high resistance and some being nearly non-existent. The devil is in the details when it comes to designing a stable circuit.
In the above circuit there are several other resistances that are being ignored for simplicity and because most of them are extremely tiny. However, one of the resistances is significant, and that it the internal resistance of the power supply.
Without the resistor shown in the schematic, the internal resistance of the battery becomes the most significant resistance in the circuit and the voltage measure at D2 would remain near zero when the switch is closed and very near zero when the switch is opened.
If the resistor shown were several thousand ohms or greater, the voltage at D2 would measure close to 5 volts when the switch is closed and zero when the switch is open (however D2 will be subject to picking up any nearby static electricity or strong electromagnetic fields when the switch is open).
To prevent D2 from being subject to spurious noise, resistors are often used between signal points and ground to dampen any such undesired noise. To better imagine how this works, imagine a 100 megohm resistor connected to D2 with the other end hanging out into the air. The unconnected end of the large resistor is acting like an antenna picking up any possible noise in the vicinity. Because the resistor shown in the diagram is so much smaller then the imaginary resistor, the noise will seem to be shorted out to ground in comparison.
In a very real sense, this schematic is telling you to add in a known resistor to ground or suffer from the effects of all the resistors not show; some being very very high resistance and some being nearly non-existent.
In the above circuit there are several other resistances that are being ignored for simplicity and because most of them are extremely tiny. However, one of the resistances is significant, and that it the internal resistance of the power supply.
Without the resistor shown in the schematic, the internal resistance of the battery becomes the most significant resistance in the circuit and the voltage measure at D2 would remain near zero when the switch is closed and very near zero when the switch is opened.
If the resisterresistor shown were several thousand ohms or greater, the voltage at D2 would measure close to 5 volts when the switch is closed and zero when the switch is open (however D2 will be subject to picking up any nearby static electricity or strong electromagnetic fields when the switch is open).
To prevent D2 from being subject to spurious noise, resistors are often used between signal points and ground to dampen any such undesired noise. To better imagine how this works, imagine a 100 megohmmeg ohm resistor connected to D2 with the other end hanging out into the air. The unconnected end of the large resistor is acting like an antenna picking up any possible noise in the vicinity. Because the resistor shown in the diagram is so much smaller then the imaginary resistor, the noise will seem to be shorted out to ground in comparison.
In a very real sense, this schematic is telling you to add in a known resistor to ground or suffer from the effects of all the resistors not show; some being very very high resistance and some being nearly non-existent. The devil is in the details when it comes to designing a stable circuit.
In the above circuit there are several other resistances that are being ignored for simplicity and because most of them are extremely tiny. However, one of the resistances is significant, and that it the internal resistance of the power supply.
Without the resistor shown in the schematic, the internal resistance of the battery becomes the most significant resistance in the circuit and the voltage measure at D2 would remain near zero when the switch is closed and very near zero when the switch is opened.
If the resister shown were several thousand ohms or greater, the voltage at D2 would measure close to 5 volts when the switch is closed and zero when the switch is open (however D2 will be subject to picking up any nearby static electricity or strong electromagnetic fields when the switch is open).
To prevent D2 from being subject to spurious noise, resistors are often used between signal points and ground to dampen any such undesired noise. To better imagine how this works, imagine a 100 megohm resistor connected to D2 with the other end hanging out into the air. The unconnected end of the large resistor is acting like an antenna picking up any possible noise in the vicinity. Because the resistor shown in the diagram is so much smaller then the imaginary resistor, the noise will seem to be shorted out to ground in comparison.
In a very real sense, this schematic is telling you to add in a known resistor to ground or suffer from the effects of all the resistors not show; some being very very high resistance and some being nearly non-existent.
In the above circuit there are several other resistances that are being ignored for simplicity and because most of them are extremely tiny. However, one of the resistances is significant, and that it the internal resistance of the power supply.
Without the resistor shown in the schematic, the internal resistance of the battery becomes the most significant resistance in the circuit and the voltage measure at D2 would remain near zero when the switch is closed and very near zero when the switch is opened.
If the resistor shown were several thousand ohms or greater, the voltage at D2 would measure close to 5 volts when the switch is closed and zero when the switch is open (however D2 will be subject to picking up any nearby static electricity or strong electromagnetic fields when the switch is open).
To prevent D2 from being subject to spurious noise, resistors are often used between signal points and ground to dampen any such undesired noise. To better imagine how this works, imagine a 100 meg ohm resistor connected to D2 with the other end hanging out into the air. The unconnected end of the large resistor is acting like an antenna picking up any possible noise in the vicinity. Because the resistor shown in the diagram is so much smaller then the imaginary resistor, the noise will seem to be shorted out to ground in comparison.
In a very real sense, this schematic is telling you to add in a known resistor to ground or suffer from the effects of all the resistors not show; some being very very high resistance and some being nearly non-existent. The devil is in the details when it comes to designing a stable circuit.
In the above circuit there are several other resistances that are being ignored for simplicity and because most of them are extremely tiny. However, one of the resistances is significant, and that it the internal resistance of the power supply.
Without the resistor shown in the schematic, the internal resistance of the battery becomes the most significant resistance in the circuit and the voltage measure at D2 would remain near zero when the switch is closed and very near zero when the switch is opened.
If the resister shown were several thousand ohms or greater, the voltage at D2 would measure close to 5 volts when the switch is closed and zero when the switch is open (however D2 will be subject to picking up any nearby static electricity or strong electromagnetic fields when the switch is open).
To prevent D2 from being subject to spurious noise, resistors are often used between signal points and ground to dampen any such undesired noise. To better imagine how this works, imagine a 100 megohm resistor connected to D2 with the other end hanging out into the air. The unconnected end of the large resistor is acting like an antenna picking up any possible noise in the vicinity. Because the resistor shown in the diagram is so much smaller then the imaginary resistor, the noise will seem to be shorted out to ground in comparison.
In a very real sense, this schematic is telling you to add in a known resistor to ground or suffer from the effects of all the resistors not show; some being very very high resistance and some being nearly non-existent.