likephysics said:What is the BJT base current if the base is connected to a zener diode like in the circuit here - http://www.satcure-focus.com/tutor/page5.htm
With a voltage divider it's thevenin's equivalent. But with zener, should I consider it as a voltage source?
To calculate the base current for a BJT in a circuit with a Zener diode, you will need to use Ohm's Law. First, determine the voltage drop across the Zener diode by subtracting the Zener voltage from the supply voltage. Then, divide this voltage by the resistance of the base-emitter junction of the BJT to determine the base current.
The Zener diode is used in a BJT circuit to regulate the voltage at the base of the transistor. It acts as a voltage reference and helps to stabilize the base current, ensuring that the transistor operates within its optimal range.
The Zener voltage has a direct impact on the base current in a BJT circuit. As the Zener voltage increases, the voltage drop across the base-emitter junction of the transistor decreases, leading to a decrease in base current. Similarly, a decrease in Zener voltage will result in an increase in base current.
Yes, it is possible to use a Zener diode with a different voltage rating in a BJT circuit. However, this will affect the base current and may impact the overall performance of the transistor. It is important to select a Zener diode with a voltage rating that is close to the desired Zener voltage for the circuit.
Yes, there are a few limitations to using a Zener diode in a BJT circuit. One limitation is that the Zener diode must be operated within its specified breakdown voltage to function properly. Additionally, the maximum current that can flow through the Zener diode must not exceed its rated value to prevent damage to the diode and the BJT circuit.