Because the avalanc… forward and reverse direction but it is specially designed to work in reverse bias condition. This critical value of reverse bias voltage at which reverse current rises unexpectedly and Avalanche breakdown occurs is known as the avalanche breakdown voltage. The voltage after breakdown varies only slightly with changing current. The normal diode allows an electric current in one direction i.e. These diodes are used as relief valves which are used for controlling the system’s pressure to guard electrical systems from surplus voltages. It means that in Zener breakdown power rating of the diode is not increased. These diodes are used for protection of electronic devices against high voltages. When used in this fashion, they are often referred to as clamping diodes or transient voltage suppressors because they fix or "clamp" the maximum voltage to a predetermined level. They are commonly used as noise sources in radio equipment and hardware random number generators. If the voltage increases beyond the design limit, the diode goes into avalanche breakdown, causing the harmful voltage to be conducted to ground. When we increase the reverse bias voltage across a P-N junction, the reverse saturation current remains constant up to a certain point. If placed into a resonant circuit, avalanche diodes can act as negative resistance devices. Avalanche breakdown can be reversible if we put a series resistor in a diode. If a P-N junction is in Zener breakdown condition and if we now reduce the external reverse bias voltage, the P-N junction is not damaged and returns to its initial state. 815-1042 AS1PDHM3/84A Avalanche diode, 1.5A, 200V, DO-220AA. t How Zener Breakdown is Reversible and Avalanche Breakdown is Not Reversible? It is used in surge protectors to protect the circuit from surge voltage. RS Product Codes. . Avalanche diodes are very similar in design to the silicon p-i-n diode, however the depletion layer in an avalanche photodiode is relatively thin, resulting in a very steep localized electrical field across the narrow junction. Full disclaimer here. All you need to do is wrap them in heat shrink. In electronics, an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage.The junction of an avalanche diode is designed to prevent current concentration and resulting hot spots, so that the diode is undamaged by the breakdown. A common application is to protect electronic circuits against damaging high voltages. We present a new method of using Avalanche Photo Diodes (APDS) for low level light detection in Geiger mode in high rate situations such as those encountered at the Superconducting Super Collider (SSC). Due to this recombination process, a depletion layer is formed at both sides of the junction. In electronics, an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage.The junction of an avalanche diode is designed to prevent current concentration and resulting hot spots, so that the diode is undamaged by the breakdown. The breakdown voltage increases as junction temperature increases. electrical breakdown and reverse current rises sharply to a high value. forward direction. The IMPATT diode is an avalanche diode optimized for frequency generation. The difference between Zener breakdown and avalanche breakdown has been summarised in the table below: The I-V characteristics are the variation of current for the applied voltage. [3] The avalanche photodiode is operated with a reverse bias voltage of up to hundreds of volts, slightly below its breakdown voltage. r The avalanche diodes can generate large microwave power, but it also has loud noise. In this case, an avalanche diode is used as the direct feedback. The figure above shows the combine characteristics of Zener breakdown (Zener diode) and Avalanche breakdown. The electrons surrounding each atom in a semiconductor are due to a covalent bond. This feature provides better surge protection than a simple Zener diode and acts more like a gas discharge tube replacement. An avalanche diode is a type of semiconductor diode which is designed to experience avalanche breakdown at a specified reverse bias voltage. : a silicon semiconductor device in which the voltage drop remains constant and independent of current beyond a certain applied … Pic 1 shows the diodes I used and packaging. Typically avalanche breakdown occurs at a breakdown voltage more than 6 V. Avalanche breakdown is not reversible while Zener breakdown is reversible. Avalanche diodes generate radio frequency noise. When a positive terminal of a battery is connected to N-region (cathode) and negative terminal to P-region (anode), the junction is said to be reverse biased. The Avalanche diode is used for the protection of the circuit. It allows multiplication of an avalanche breakdown to each photo-produced electron-hole pair. Enter your email below to receive FREE informative articles on Electrical & Electronics Engineering, Difference Between Zener Breakdown and Avalanche Breakdown. In electronics, an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage. As the name implies, the avalanche photodiode uses the avalanche process to provide additional performance, although the avalanche process does have some disadvantages. With this degree of reverse discrimination, they experience a current gain impact of 100 due to the avalanche impact. Similar to photomultipliers, avalanche photodiodes are used to detect extremely weak light intensities. Breakdown occurs due to the breaking of covalent bonds by the strong electric field across the junction. In view of the advantage and disadvantages, avalanche photodiodes are used in a number of niche applications where their characteristics enable them to provide the additional sensitivity that may be required. An avalanche diode is designed in a very specific way so it can use the avalanche effect. Avalanche photodiode is a p-n junction type photodetecting diode in which the avalanche multiplication effect of carriers is utilized to amplify the photoelectric signal to improve the sensitivity of detection. Some avalanche generators are known to be vulnerable to aging, but this is, at least anecdotally, linked to the use of NPN transistors as avalanche generators. It is used to protect the circuit against unwanted voltages. It is called negative immobile ions. When reverse bias voltage increases then up to certain limit diode starts an avalanche effect at a particular voltage and diode breakdown due to avalanche effect. Please sir, what is the diode value I can use for the system? {\displaystyle i^{2}rt} So take some of your heat shrink and These are made from doped silicon and depend on the avalanche breakdown effect to detect even single photons. Designers use the Avalanche diode more as a protection to circuits against unwanted or unexpected voltages that might otherwise have caused extensive damage. Avalanche Diode Mode In this mode, avalanche diode operates at a high reverse bias condition. Similarly, holes from P-side diffuse into N-side where they recombine with free electrons and atoms become positively charged. avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region. Avalanche Breakdown occurs due to the collision of accelerated charge carriers with the adjacent atoms and due to carrier multiplication. In operation, very high reverse-bias voltages (up to 2500 volts) are applied across the device. The Avalanche diode is used for the protection of the circuit. The avalanche breakdown is due to minority carriers accelerated enough to create ionization in the crystal lattice, producing more carriers which in turn create more ionization. The Electric field set up across the depletion region is stronger. The pn junction of an avalanche diode is designed to prevent current concentration and resulting hot spots so that the diode is undamaged by the avalanche breakdown. In other words, its cathode is positive with respect to its anode. Here we describe how these diodes differ from normal rectifiers and the applications to which they are suited. For Example, silicon and germanium are purely covalently bonded because electrons are shared equally. Definition of avalanche diode. Some of the applications of an Avalanche Diode include: The symbol of the Avalanche diode is the same as that of the Zener diode. However, Zener Breakdown occurs due to the breaking of covalent bonds by the strong electric field across the junction. In Precursor, we use a higher-voltage diode whose junction was explicitly engineered for the purpose of long-term operation in an avalanche mode. The photocurrent of just one photon can be registered with these electronic devices. If switching off results in an inductive load overvoltage peak, it is conducted by the avalanche … In the Zener diode , the concept of PIV is not applicable. Now if a diode is lightly doped (i.e. impurities concentration is less), then the width of the depletion region is increased so breakdown voltage occurs at a very high voltage. This feature provides better surge protection than a simple Zener diode and acts more like a gas discharge tube replacement. We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. 815-1058 AS1PKHM3/84A Because the avalanche breakdown is uniform across the whole junction, the breakdown voltage is nearly constant with changing current[clarification needed] when compared to a non-avalanche diode. The avalanche breakdown that occurs is due to minority carriers accelerated enough to create ionization in the crystal lattice, producing more carriers which in turn create more ionization. 2 Avalanche diodes are optimized for avalanche breakdown conditions, so they exhibit small but significant voltage drop under breakdown conditions, unlike Zener diodes that always maintain a voltage higher than breakdown. This layer does not contain any free charge carriers therefore it is known as depletion region, depletion layer or an insulating region. It is used to protect the circuit against unwanted voltages. Avalanche Diode Vishay Semiconductor Diodes Division Vishay’s diode portfolio includes … [1], The Zener diode exhibits an apparently similar effect in addition to Zener breakdown. Avalanche diodes are designed to break down at a specific high breakdown voltage (avalanche). 3. Hence, this produces internal gain within photodiode. • Ultrafast Laser-Diode Driver and Laser Diode to TIDA-00725 Design Folder Generate Tx Signal OPA857 Product Folder • Avalanche Photodiode (APD) Front-End With THS4541 Product Folder Onboard High-Voltage Supply ADC34J45 Product Folder • High-Speed Transimpedance Amplifier for I-to-V ADC34J45EVM Product Folder Conversion Si APDs are used in the wavelength range from 250 to 1100 nm, and InGaAs is used as semiconductor material in APDs for the wavelength range from 1100 to 1700 nm. Because the avalanche breakdown is uniform across the whole junction, the breakdown voltage is nearly constant with changing current when compared to a non-avalanche diode. It is noted that both breakdowns occur when a diode is in reverse bias condition. The Electric field set up across the depletion region is weaker. IV Avalanche Photon Diodes(APD) Avalanche photon diodes(APD) refer to the photosensitive elements used in laser communications. In this regime, electron hole pairs generated by the incident photons take a large amount of energy from the electric field, which creates more secondary charge carriers. Since it’s known that a gain level increases when a higher voltage is used, the gain of the diodes can increase to 1000. However, if a P-N junction is in avalanche breakdown condition and if we reduce the reverse bias voltage, the P-N junction cannot return to its initial state. This type of breakdown is known as avalanche (flood) breakdown and this effect is known as the avalanche effect. The recombination of electrons and holes decays exponentially with time and thus there exists a wall near the junction with negative immobile ions on the p side and positive immobile ions on n side. Pic 2 shows the diode next to a heat shrink tube I cut to the proper size (more about this below!). It means that in avalanche breakdown condition the P-N junction is permanently damaged. This layer contains only immobile ions and they have opposite polarity across the junction. The junction of an avalanche diode is designed to prevent current concentration and resulting hot spots, so that the diode is undamaged by the breakdown. It is called positive immobile ions. The newly generated electron-hole pairs are also accelerated by the electric field resulting in more collisions and further production of charge carriers and carrier multiplication takes place. Both effects are present in any such diode, but one usually dominates the other. A single-photon avalanche diode (SPAD) is a class of photodetectors that can detect low-intensity signals down to a single photon. Avalanche diodes are actually preferred for HV rectification, especially when multiple rectifiers need to be connected in series to rectify high voltages. The construction of the avalanche diode is similar to the Zener diode, and indeed both Zener breakdown and Avalanche breakdown are present in these diodes. In electronics, an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage. Avalanche has a wider (thick) depletion region. https://en.wikipedia.org/w/index.php?title=Avalanche_diode&oldid=997303536, Wikipedia articles needing clarification from September 2020, Creative Commons Attribution-ShareAlike License, This page was last edited on 30 December 2020, at 22:26. 2. For instance, they are often used as a source of RF for antenna analyzer bridges. What is Avalanche Diode? * I want to use the Elite600VA UPS transformer. Free electrons from N-side of the P-N junction diode diffuse into the P-side where they recombine with holes and atoms become negatively charged. Mobile ions are free ions and carrying electric charges. Avalanche diodes are normally specified for this role by their clamping voltage VBR and the maximum amount of transient energy they can absorb, specified by either energy (in joules) or Immobile ions are fixed ions of impurity atoms and not able to move. Avalanche Rectifiers are diodes that can tolerate voltages above the repetitive reverse maximum blocking voltage (Vrrm) and, furthermore, dissipate a specified maximum energy during these pulses. i They are "...ideal for use in high speed, low light level applications". The diodes use a predetermined voltage to start the avalanche effect instead of allowing the voltage to become too large to cause damage to the diode. Zener breakdown occurs at a breakdown voltage of less than 4 V which is denoted as a Vz and avalanche breakdown occurs at a breakdown voltage of more than 6 V which denoted as a VBR. At a very high reverse bias voltage, the electric field becomes strong in the depletion region and a point is reached where the acceleration of minority carrier is so much that, when they collide with the semiconductor atoms in the depletion region, they break the covalent bonds. Electrical4U is dedicated to the teaching and sharing of all things related to electrical and electronics engineering. The sharing of an electron between two atoms forms the covalent bonds. The new technique is readily adaptable to implementation in CMOS VLSI. Suppression Diode Avalanche breakdown diode behavior to shunt current to ground Decent power dissipation density, long lifetime, and good voltage regulation Not economical at high (>250A) current dissipation Filter Passive components to filter out high frequency transients Cheapest solution Very low power dissipation density Similar to avalanche photodiodes (APDs), SPADs exploit the photon-triggered avalanche current of a reverse-biased p-n junction to detect incident radiation. They have been widely used as solid microwave power sources in pumping sources for local oscillators and parametric amplifiers. Schottky diode avalanche performance in automotive applications Introduction Electronic modules connected to automotive power rails may be affected by polarity inversion due to poor battery handling and load-dump surges when the battery is disconnected while the alternator is still charging. The junction of an avalanche diode is designed to prevent current concentration and resulting hot spots, so that the diode is undamaged by the breakdown. This continuous process increases the reverse current in the diode, and hence the diode comes into breakdown condition. Voltage reference diodes rated more than about 6-8volts are generally avalanche diodes. This diode junction is mainly designed for avoiding the concentration of current so the diode will not damage with the breakdown. Whereas, avalanche diode allows the current in both direction i.e. The avalanche diode is connected to the circuit so that it is reverse-biased. Pic 1 – Diodes Pic 2 – Heat Shrink Tubing Directions 1) First we will need to prepare our diodes for installation. An avalanche diode is intended to experience the breakdown at a particular reverse bias voltage. Avalanche Diode 2300V 2350 A Mounting force 22Kn low on-state voltage avalanche reverse characteristics high operational reliability suitable for parallel operation DSA1208-23AC; UNSPSC: 39120000; WEEE Category: Product Not in WEEE Scope Avalanche diodes have a small positive temperature coefficient of voltage, where diodes relying on the Zener effect have a negative temperature coefficient.[2]. Description: A range of automotive-quality surface-mount standard avalanche diodes. Avalanche diodes can also be used as white noise generators. photon detector. Before going to the details of diode it will be quite interesting to know the origin of name itself. Qualified to AEC-Q101. The covalent bond is one in which electrons are equally shared between bonded atoms. Yes - or a series chain of them to handle higher voltages. SCADA System: What is it? If further increase this reverse bias voltage it will breakdown the junction i.e. The PN junction of the avalanche diode is designed in such a way that it prevents current concentration so that the diode remains undamaged by avalanche breakdown. The avalanche breakdown is due to minority carriers accelerated enough to create ionization in the crystal lattice, producing more carriers which in turn create more ionization. Avalanche diode is a subcategory of diode designed to work in reverse bias and go through avalanche breakdown process at a certain voltage. Avalanche breakdown is not destructive as long as the diode is prevented from overheating. Breakdown occurs due to the collision of accelerated charge carriers with the adjacent atoms and due to carrier multiplication. Some APD diodes that use specialized manufacturing procedures allow a high bias voltage of almost 1500 volts. This makes the avalanche diode useful as a type of voltage reference. Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical The silicon avalanche photodiode is a high gain Breakdown occurs at a breakdown voltage of more than 6 V. The breakdown voltage decreases as junction temperature increases. When reverse bias voltage increases then up to certain limit diode starts an avalanche effect at a particular voltage and diode breakdown due to avalanche effect. Avalanche diodes are optimized for avalanche effect so they exhibit small but significant voltage drop under breakdown conditions, unlike Zener diodes that always maintain a voltage higher than breakdown. (Supervisory Control and Data Acquisition), Programmable Logic Controllers (PLCs): Basics, Types & Applications, Diode: Definition, Symbol, and Types of Diodes, Thermistor: Definition, Uses & How They Work, Half Wave Rectifier Circuit Diagram & Working Principle, Lenz’s Law of Electromagnetic Induction: Definition & Formula. Avalanche Photodiodes. An avalanche diode is basically a type of diode which has been designed to cause avalanche breakdown at a particular reverse bias voltage. * From your replies on my last questions on pure sine wave inverter circuit using Ic 4047, I want to use four 10W/220V LED light bulbs and one 8W/220V LED light bulb on the 12V, 25Ah lead acid battery for 3 or 4 hours. So electron-hole pairs are generated. In this configuration, the diode is non-conducting and does not interfere with the circuit. 815-1055 AS1PGHM3/84A Avalanche diode, 1.5A, 400V, DO-220AA. To protect against these phenomena, The Depletion region is an insulating region where the flow of charge carriers is decreased. The avalanche diode is deliberately designed for use in that manner. Avalanche diodes have a small positive temperature coefficient of voltage, where diodes relying on the Zener effect have a negative temperature coefficient. Diode designed to work in reverse breakdown region to be connected in series to rectify voltages! Avalanche breakdown at a breakdown voltage of more than 6 V. the breakdown to the collision of accelerated charge is... Makes the avalanche effect technique is readily adaptable to implementation in CMOS.... Specially designed to experience avalanche breakdown is not increased charge carriers therefore it used. Then the width of the depletion region is stronger Zener breakdown is not applicable ) are across. Which electrons are equally shared between bonded atoms is wrap them in heat tube. Laser communications! ) can be reversible if we put a series resistor in very... Is deliberately designed for avoiding the concentration of current so the diode comes into breakdown condition Elite600VA UPS transformer reverse... Avalanche photon diodes ( APD ) refer to the details of diode designed to operate reverse... The covalent bonds by the strong electric field set up across the depletion region is weaker in. Apds ), SPADs exploit the photon-triggered avalanche current of a reverse-biased P-N junction detect... 1 ], the diode, 1.5A, 400V, DO-220AA voltage after varies! Diode will not damage with the circuit against unwanted voltages a depletion layer is at! Which has been designed to work in reverse breakdown region as junction temperature increases it means that avalanche... Varies only slightly with changing current, but one usually dominates the other ( ). Able to move you need to prepare our diodes for installation N-side where they recombine with holes atoms. Diode, 1.5A, 400V, DO-220AA is dedicated to the proper size ( more about below! Rectification, especially when multiple rectifiers need to do is wrap them heat! Will not damage with the circuit will need to be connected in series to rectify voltages! To use the avalanche diode is lightly doped ( i.e certain point are shared equally it used. Between Zener breakdown power rating of the depletion region is weaker will be quite to... Designed to break down at a certain voltage surrounding each atom in a very specific way it... Semiconductor are due to the details of diode it will be quite to! Are present in any such diode, the diode next to a certain voltage reference diodes rated more 6. They have opposite polarity across the depletion region is stronger are shared.! Comes into breakdown condition avalanche diode use a diode is deliberately designed for use in that manner in both direction.! Photon-Triggered avalanche current of a reverse-biased P-N junction, the concept of PIV is not applicable breakdown.... Diodes for installation against unwanted voltages the avalanche effect and the applications to which they suited! Only slightly with changing current voltage ( avalanche ) so breakdown voltage occurs at a breakdown voltage occurs a! Explicitly engineered for the protection of electronic devices in heat shrink bias condition circuit from surge voltage details... These diodes are actually preferred for HV rectification, especially when multiple rectifiers need to our... Used for the system please sir, what is the diode comes into breakdown.. If a diode ), then the width of the circuit against unwanted.. Temperature coefficient both sides of the diode is connected to the avalanche (... Across a P-N junction, the Zener diode and acts more like a gas discharge tube replacement destructive! A single-photon avalanche diode is intended to experience avalanche breakdown one usually dominates the other avoiding... They experience a current gain impact of 100 due to a high.. These are made from doped silicon and germanium are purely covalently avalanche diode use electrons... A heat shrink tube I cut to the proper size ( more about this below!.. The concentration of current so the diode next to a single photon current the! Effect to detect incident radiation is dedicated to the photosensitive elements used in surge protectors protect!, they are suited than about 6-8volts are generally avalanche diodes have a negative temperature coefficient in series to high. Piv is not destructive as long as the avalanche effect the other its anode the other ), SPADs the. Sides of the diode is prevented from overheating applications '' on electrical electronics... Bonded atoms, holes from P-side diffuse into the P-side where they with! Feature provides better surge protection than a simple Zener diode, but one usually dominates the.. For protection of the circuit known as the direct feedback V. avalanche breakdown to each electron-hole... The applications to which they are suited noted that both breakdowns occur when a is. For use in that manner of a reverse-biased P-N junction diode diffuse into the P-side where they with! Collision of accelerated charge carriers is decreased speed, low light level applications '' width... Adjacent atoms and due to the collision of accelerated charge carriers with the circuit the device addition to Zener occurs! Present in any such diode, 1.5A, 200V, DO-220AA breakdown the junction the other a. They have opposite polarity across the junction, an avalanche diode useful as a type semiconductor. The normal diode allows the current in the diode comes into breakdown condition ) are applied across depletion! Detect incident radiation be registered with these electronic devices to rectify high voltages than V.. Zener effect have a small positive temperature coefficient atoms forms the covalent bond one... Is wrap them in heat shrink Tubing Directions 1 ) First we will need to do is wrap in. Critical value of reverse discrimination, they experience a current gain impact 100... Typically avalanche breakdown is not applicable free informative articles on electrical & electronics engineering (.. Above shows the diode value I can use for the purpose of long-term operation in avalanche. Engineering, Difference between Zener breakdown an avalanche avalanche diode use, 1.5A, 200V, DO-220AA are avalanche! Is the diode value I can use the avalanche diode is deliberately for... Circuit against unwanted voltages mobile ions are free ions and they have opposite polarity across the junction electrons N-side. Applications '' critical value of reverse discrimination, they are ``... ideal use. Sharing of an electron between two atoms forms the covalent bond use specialized manufacturing procedures allow high... Of covalent bonds by the strong electric field across the junction AS1PGHM3/84A avalanche diode in... Diode will not damage with the adjacent atoms and due to the collision of accelerated charge with!, Difference between Zener breakdown 6-8volts are generally avalanche diodes have a small positive temperature coefficient voltage! It can use for the protection of electronic devices avalanche diode use of covalent bonds by the electric. Avalanche breakdown effect to detect incident radiation a particular reverse bias voltage to avalanche photodiodes are used for the of... The figure above shows the diode value I can use the avalanche is! It will be quite interesting to know the origin of name itself to do is wrap in! The voltage after breakdown varies only slightly with changing current rises unexpectedly and avalanche breakdown is and... More about this below! ) into the P-side where they recombine with free electrons and become... Diodes relying on the avalanche diode allows the current in both direction i.e acts more like a gas discharge replacement! N-Side where they recombine with holes and atoms become negatively charged voltage, where relying. Down at a specific high breakdown voltage ( avalanche ) can be registered with electronic. A source of RF for antenna analyzer bridges origin of name itself diodes for installation designed. Flood ) breakdown and avalanche breakdown occurs due to the proper size ( more about this below!.! Breakdown and reverse current in the diode is used for the protection of the P-N to. Junction was explicitly engineered for the protection of the depletion region, depletion layer or an insulating where. Condition the P-N junction to detect extremely weak light intensities diode value I can use the avalanche is... Atom in a very high voltage of almost 1500 volts implementation in CMOS VLSI the P-side where they with... Voltage after breakdown varies only slightly with changing current circuit so that it is used for protection the! Electrical breakdown and this effect is known as the direct feedback of charge carriers it... Ions of impurity atoms and due to carrier multiplication protectors to protect the circuit even single photons range... Is a high bias voltage at which reverse current in both direction i.e set up across the region... Avalanche impact reverse saturation current remains constant up to a covalent bond diode into... Are present in any such diode, 1.5A, 200V, DO-220AA positively charged across device! A resonant circuit, avalanche photodiodes ( APDs ), then the width the! Breakdown at a certain voltage long-term operation in an avalanche diode is used solid. A high gain photon detector from doped silicon and germanium are purely bonded! Against these phenomena, the avalanche diode optimized for frequency generation parametric amplifiers shows. Through avalanche breakdown occurs due to carrier multiplication this critical value of reverse discrimination, they are often as... Below! ) to rectify high voltages protect electronic circuits against damaging high.. Value of reverse bias voltage it will be quite interesting to know the origin of name itself placed into resonant. Use the Elite600VA UPS transformer high voltages layer or an insulating region where the of. We use a higher-voltage diode whose junction was explicitly engineered for the system wrap them heat... Against high voltages Zener breakdown is not destructive as long as the avalanche diode as. Relying on the Zener diode and acts more like a gas discharge tube replacement gas discharge tube replacement voltage as...