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Raymond31415
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When do you use an internal substrate connection vs an external substrate connection on a depletion mode transistor?
Raymond31415 said:When do you use an internal substrate connection vs an external substrate connection on a depletion mode transistor?
Raymond31415 said:I don't know what the difference in function is between an internal vs an external connection, I had just happen to see a schematic for both online, and I haven't been able to find anything to read about one vs the other.
A depletion mode transistor is a type of field-effect transistor (FET) that operates in a state in which the channel between the source and drain is already conductive without the need for an applied voltage. This is in contrast to enhancement mode transistors, which require a certain voltage to be applied in order to become conductive.
A depletion mode transistor has a constant channel of conductive material between the source and drain, and is controlled by a gate voltage. When a voltage is applied to the gate, it creates an electric field that repels the majority carriers in the channel, effectively reducing its conductivity. This allows the transistor to be turned off by applying a negative voltage to the gate, and turned on by applying a positive voltage.
Depletion mode transistors have a higher input impedance and lower noise compared to other types of transistors. They also have a simpler circuit design, as they do not require an external voltage source to turn on. Additionally, depletion mode transistors have a lower threshold voltage, making them more energy efficient.
Depletion mode transistors are commonly used in low-noise amplifiers, voltage-controlled oscillators, and switching circuits. They are also used in power management systems, as they have low power consumption and high switching speeds.
The main difference between depletion mode and enhancement mode transistors is their operating states. Depletion mode transistors are normally on and require a negative voltage to turn off, while enhancement mode transistors are normally off and require a positive voltage to turn on. Additionally, depletion mode transistors have a higher input impedance and lower threshold voltage compared to enhancement mode transistors.