How to calculate collector current and voltage In LTspice?
Fig. 4.4: The LTSpice generated circuit netlist for calculating the collector current and voltage of the transistor circuit shown in Fig. 4.3. Assuming the nodes of the circuit are labeled as shown in Fig. 4.3, the corresponding LTSpice generated netlist (with some rearrangements) is listed in Fig. 4.4.
What are the ohmic resistances of the Spice BJT?
The Spice BJT model is illustrated schematically in Fig. 4.2. The ohmic resistances of the base, collector, and emitter regions of the BJT are lumped into three linear resistances r B, r C and r E , respectively.
What kind of circuits can be simulated In LTspice?
The types of circuits that will be simulated will range from single npn and pnp transistor amplifiers to multiple-transistor amplifier circuits, as well as circuits that utilize the transistor as an on-off switch. Two statements are required to describe any particular semiconductor device to LTSpice.
How is base temperature dependence modeled In LTspice?
Additionally base current temperature dependence is modeled by the beta temperature exponent XTB in the new model. The values specified are assumed to have been measured at the temperature TNOM, which can be specified on the .OPTIONS control line or overridden by a specification on the .model line.
How to describe a bipolar junction transistor ( BJT ) to spice?
In this chapter on the bipolar junction transistor (BJT) we shall proceed in a similar fashion, first outlining the two statements that are required to describe a BJT to Spice. This will then be followed by a brief description of the model used to represent the BJT within Spice.
How to calculate collector current in BJT beta variations?
We saw in the previous article that BJT beta is both simple and complex: simple, because all you need to do to calculate collector current is multiply base current by beta; complex, because there are several betas to choose from.
How is the DC operating point of a BJT calculated?
Fig. 4.3: Transistor BJT amplifier circuit captured by LTSpice. LTSpice is used to calculate the DC operating point of this circuit assuming a simple model of BJT operation. Fig. 4.4: The LTSpice generated circuit netlist for calculating the collector current and voltage of the transistor circuit shown in Fig. 4.3.