0
What is the purpose of connecting two zener diodes back to back?
Wiki User
∙ 11y ago
The back to back connected zener diodes can be used as an AC regulator producing what is jokingly called a "poor man's square wave generator". Using this arrangement we can clip the waveform between a positive value of +8.2V and a negative value of -8.2V for a 7.5V zener diode. If we wanted to clip an output waveform between different minimum and maximum values for example, +8V and -6V, use would simply use two differently rated zener diodes.
http://www.electronics-tutorials.ws/diode/diode_7.html
Wiki User
∙ 11y ago
Wiki User
∙ 10y agoNo reason at all, besides:
Redundancy or Load Balancing
(if a 5V circuit shall be protected from over-voltage, and if the input is protected with a 2A fuse, the zener diodes all together need to withstand up to 10W until the fuse breaks).
Wiki User
∙ 12y agoWhen two zener diodes are connected in parallel, since no two diodes are exactly the same, one will conduct at a slightly different point than the other, so that most of the current will go through only one, making the other one useless.
Add your answer:
Earn +20 pts
Can you make a transistor by connecting two diodes back to back?
Two diodes, whether or not discreet, cannot work together as a transistor. The diodes and transistor have different profiles to optimize them for their specific functions
How does a zener diode work in forward bias?
Like a normal diode............. unless it includes a "back biased" diode to prevent conduction in this mode as is common in zener diodes rated at about 10 volts or more, then it acts as an open circuit.
How much voltage appears across a zener diode when it is forward-biased?
That depends on the zener voltage rating:"low voltage" zeners are just a simple single diode, the zener diode"high voltage" zeners contain 2 back to back diodes in one package, the zener diode and an ordinary diode that is reverse biased when the zener diode is forward biased to block forward conduction of the zener and protect it from overcurrent damage if installed backwards by mistakeThus in "low voltage" zeners when forward biased they will have a normal diode drop (e.g. 0.7V), but "high voltage" zeners when "forward biased" they will act open due to the reverse biased blocking/protection diode in series with the zener.
What is a thyrector diode?
A Thyrector is essentially two zener diodes connected back-to-back in opposing polarity which means it will not conduct until an over-voltage above its break-down voltage rating occurs. This is used to trap voltage spikes and suppress them.
What will happens if zener diode and resistance are connected in parallel?
If diode is connected in series then current will flow only in one direction. ie. Current flow occurs only when diode is forward biased. ANSWER: It depends are the diodes are connected in series if they are back to back no current will flow if connected in the forward conduction mode then they will conduct.
Can you make a transistor by connecting two diodes back to back?
Two diodes, whether or not discreet, cannot work together as a transistor. The diodes and transistor have different profiles to optimize them for their specific functions
How many diode makes one transistor?
When investigated with an ohm-meter, a transistor resembles two diodes connected "back-to-back". But you can't make a transistor by connecting two diodes back-to-back.
How does a zener diode work in forward bias?
Like a normal diode............. unless it includes a "back biased" diode to prevent conduction in this mode as is common in zener diodes rated at about 10 volts or more, then it acts as an open circuit.
Why dont we get the transister action by connecting two diodes back to back?
Because two diodes is not a transistor. There is an interaction between the junctions in the transistor, because of their proximity, that you don't get in the two diodes. The only use of modeling a transistor as two diodes back to back is to test a transistor with a multimeter as a quick go-nogo test for basic operability.
Are diode forward and zener voltages the same?
A: Both diodes have the same curve in the forward direction however if the zener voltage is reverse it will breakdown at a particular voltage and remain conducting at the voltage. A regular diode will not do that the to voltage will fold back after breakdown to any voltage
How much voltage appears across a zener diode when it is forward-biased?
That depends on the zener voltage rating:"low voltage" zeners are just a simple single diode, the zener diode"high voltage" zeners contain 2 back to back diodes in one package, the zener diode and an ordinary diode that is reverse biased when the zener diode is forward biased to block forward conduction of the zener and protect it from overcurrent damage if installed backwards by mistakeThus in "low voltage" zeners when forward biased they will have a normal diode drop (e.g. 0.7V), but "high voltage" zeners when "forward biased" they will act open due to the reverse biased blocking/protection diode in series with the zener.
How can you designed transistor using diode because no available transistor?
You cannot build a transistor with two diodes. Even though the static junction characteristics of a transistor "looks like" two back to back series diodes, there is a relationship between the two junctions that cannot be matched by just connecting two diodes together.
What is a thyrector diode?
A Thyrector is essentially two zener diodes connected back-to-back in opposing polarity which means it will not conduct until an over-voltage above its break-down voltage rating occurs. This is used to trap voltage spikes and suppress them.
What will happens if zener diode and resistance are connected in parallel?
If diode is connected in series then current will flow only in one direction. ie. Current flow occurs only when diode is forward biased. ANSWER: It depends are the diodes are connected in series if they are back to back no current will flow if connected in the forward conduction mode then they will conduct.
How does the selenium diode work?
Selenium diodes work much like any other diode. They allow current to flow in a forward direction and block current from flowing in the opposite direction. They have a higher forward bias voltage then silicon and as such generate much more heat then a comparable silicon diode. Most selenium diodes will therefore have an integrated heat sink that helps to dissipate all the heat generated. As a zener diode, selenium is used in surge suppression where its heat sink helps in survivability during a surge. However, its low alpha (measure of nonlinearity) means that the voltage during a surge is very high and usually unsuitable to be used as protective device without other components in parallel. The reverse voltage is about 26 Volts, so to get higher voltage zener diode, many are placed in series. By connecting them back to back, then a bidirectionial zener diode can be created. Selenium diode were very common in the 1950s and can be seen in industrial applications of the time. Some model train power supplies were seen to use these components. Since the advent of silicon diodes and their more efficient operation, these part have disappeared from use.
What is back to back diode?
A: Refers two two diodes connected as it say back to back for gates applications.
You want to solder a broken zener diode back together with liquid solder?
This is not possible. You must replace the diode.
