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What is the power flowing in a 20 ohm resistor with 5A current?
20*5=100v 100v*5a=500va
In the voltage stabilizing circuit composed of silicon voltage stabilizing diode and current limiting resistor, how does the current limiting resistor compensate the voltage drop and how to select the specific resistance value?
I heard that the current limiting resistor is used to protect the voltage regulator. If the current limiting resistor is not needed, can the voltage regulator be slightly larger? According to the principle of the voltage regulator diode, as long as it works in the reverse breakdown area, can the voltage at both ends of the voltage regulator be kept basically unchanged? What is the need for the current limiting resistor? Also, when selecting the voltage regulator, how much lower should its stable voltage be than the input voltage?
In this way, if the voltage U loaded on the zener diode is much higher than the voltage UZ stabilized by the zener diode, then their difference u-uz = Δ u will fall on the wires around the zener diode. According to Ohm's theorem, I = Δ U / R, the resistance value of the wires is very small. Even if the internal resistance of the zener diode is small, the current I will be very large, It will make the stabilizer tube hot and may burn out
Generally, when selecting voltage regulator, 12V and below voltage can be connected in series with a 1K resistor
Can the current limiting resistance in front of the voltage stabilizing diode in the voltage stabilizing circuit be o ohm?
Such as title, reading confused
The current limiting resistor in front of the voltage stabilizing diode in the voltage stabilizing circuit is actually a voltage dividing resistor, and the voltage drop at both ends ur = IR. In the circuit in series with the voltage stabilizing diode, when the total voltage U fluctuates, R is regarded as a constant, then ur fluctuates with I, and the voltage at both ends of the voltage stabilizing diode basically remains unchanged, achieving a simple voltage stabilizing effect, And the I caused by the fluctuating u applied to the voltage stabilizing tube loses the limiting effect of resistance R, and it is likely to burn the voltage stabilizing tube
Calculation of current limiting resistance in voltage stabilizing circuit of voltage stabilizing tube
The formula is U / (Izm + iomin)
Answer: 1. When the grid voltage is the highest and the load current is the smallest, iz is the largest, which is not allowed to exceed the allowable value. So R ＞ (uimax VZ) / (Izm + iomin) 2. When the grid voltage is the lowest and the load current is the largest, iz is the smallest, which is not less than iz minimum. So R ＜ (uimin VZ) / (izmin + iomiax) so the selection of voltage stabilizing resistor
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