Finding total circuit current consumption for BJT amp

In summary, to measure the total power consumed by a common base BJT amplifier, one would measure the voltage from Rc down to Re (inclusive) and take a current measurement from between Vcc and Rc, and then multiply the two values together. This method may vary depending on how the circuit is drawn and biased, but one easy way to measure it is to use a small sense resistor in the power supply connection and calculate the current consumption using Ohm's law.
  • #1
Physicist3
104
0
For a common base bjt amp, would I be correct in thinking that to measure total power consumed by the circuit, you would measure voltage from Rc down to Re (inclusive) and take a current measurement from between Vcc and Rc and then multiply together?
 
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  • #2
Physicist3 said:
For a common base bjt amp, would I be correct in thinking that to measure total power consumed by the circuit, you would measure voltage from Rc down to Re (inclusive) and take a current measurement from between Vcc and Rc and then multiply together?

It may depend on how you draw the circuit, and how you bias it. In this configuration below, the current consumption from the power supply should be pretty apparent:

http://autonopedia.org/wp-content/uploads/crafts-and-technology/electronics/Common_base.png

http://autonopedia.org/wp-content/uploads/crafts-and-technology/electronics/Common_base.png
 
  • #3
The easiest way to measure it is to put a small sense resistor in the power supply connection (where small here means small enough to make the IR drop not an issue). Then you can calculate the current consumption from Ohm's law.
 

1. How is total circuit current consumption calculated for a BJT amplifier?

Total circuit current consumption for a BJT amplifier is calculated using the formula ITOTAL = IB + IC, where IB is the base current and IC is the collector current.

2. What factors affect the total current consumption in a BJT amplifier?

The total current consumption in a BJT amplifier is affected by the base current, collector current, and the gain of the transistor. Other factors that can impact the total current consumption include temperature, voltage, and the input signal.

3. How does the collector current affect the total current consumption in a BJT amplifier?

The collector current is a main factor in determining the total current consumption in a BJT amplifier. The higher the collector current, the higher the total current consumption will be. This is because the collector current is the main current flowing through the amplifier circuit.

4. Can the total current consumption in a BJT amplifier be reduced?

Yes, the total current consumption in a BJT amplifier can be reduced by using a smaller base current and by controlling the collector current. This can be done by adjusting the biasing resistors and using the appropriate values for the input signal and power supply voltage.

5. How does the gain of a transistor affect the total current consumption in a BJT amplifier?

The gain of a transistor is a measure of its amplification capabilities. A higher gain transistor will require a smaller base current to achieve the same collector current, resulting in lower total current consumption. However, using a transistor with a very high gain can also lead to potential stability issues in the amplifier circuit.

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