No. A zener diode alone will not work. If the voltage exceeds the zener voltage, the zener diode will die a quick death followed by the gauge. You need to put a resistor ahead of the zener diode and the gauge. The gauge will still read the zener voltage, not zero.
A diode from base to emitter will protect against excess reverse bias. The diode arrow direction would be opposite the direction of the base-emitter junction arrow.
Looking for advice on how to correctly identify those tiny, glass, red/black diodes. Like these: I have a couple small projects where I need a zener, I have several suspects but with no visible identifying marks I'm not sure if they are Zener or regular. (the first pic has ID marks.. ignore...
Only in this connection NPN transistor work as a Zener diode. But the Zener voltage is not well defined. This voltage will be in range between 6V up to 9V. Depending on the type of transistor we use in the circuit. So this BJT Zener diode is poor man's Zener diode. So we almost never use it. Sometime we use NPN transistor in ordinary diode ...
If you don't want to edit the standard.dio file you can get a reasonable 3V zener model thus :- Place a diode symbol on your schematic. Click 'Pick new diode'. Click on an arbitrary low voltage zener diode. Copy the highlighted text. Paste it as a command on your schematic. Edit the BV value to 3.0. Bear in mind that a real-world 3V zener diode doesn't have a very sharp voltage knee.
Your 1N4733A zener diode is 5.1V (plus or minus 5%) only when its current is the "test " current of 49mA and the zener diode is cooled somehow to 25 degrees C. Less current reduces its voltage and more current increases its voltage. Higher temperature increases its voltage. Then why do you want to spoil its voltage regulation by using low and high current? Use a voltage regulator IC instead.
The Zener diode as a reference is like a seesaw at the balance point where voltage and current are in a stable configuration. If you try to draw current away from the Zener diode you will upset the balance and loose the relationship between voltage and current.
Trying too different circuits producing noise, I get 0 Volts output running the circuits in LTspice. One circuit obtains noise from a Zener diode, and the other one from the reverse-biased emitter-base junction of a NPN bipolar transistor. Am I doing something wrong, or is LTspice not capable...
A zener diode voltage regulator is the very least efficient scheme possible, in addition to being a poor regulator . A 12 volt zener can work quite well as the reference source in a simple series pass regulator circuit.
Hello, Genarally we use zener diode in reverved biased operation. We need to make sure the current is within the spec in order to get In my simulation ,The 1N750 get 1.4mA currect when its reversed biaed to 4.7V. In the table below they say that maximal reversed currect is 5uA a thounthand times...
