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70 Threads found on Zener And Regulator
The aim is to prevent battery voltage from going over 13.8 volts or so. This simple zener and NPN regulator might be PV panel voltage varies according to how much current you draw from it. No-load maxi
I have used a NPN power transistor (BD137) plus a 270Ω resistor and a 5V zener to make a regulator which gives me a 4.4V output which is still too high. BD137 isn't suited for 2A load, neither in terms of rated current nor power disspation.
Simple transistor and zener regulator. (The zener can also be a combination of diodes/ led's/ current goes through the load, so it may not be satisfactory with every load.
Your zener has Little Rejection of Line Interference. It would be Better to use a Linear regulator, such as a 78L05.
Your schematic shows no filter, it is simply a voltage limiter consisting of R 65 and CR 11 (a zener diode). The capacitor is not necessary. If it might filter anything then one will need to know the Vin source impedance.
Thanks all, Do you have any idea why they used 220/15V transformer and then used zener to regulate voltage to 3.3V ?! why didn't they use lower voltage transformer instead of 15V ? the higher voltage just makes much loss power on zener or the regulator ! and about life time ? which type usually has longer (...)
This is basically a continuous Buck regulator switching oscillator than regulates the pulse width for an average DC voltage across Vbe controlled by D1 zener voltage , Vbe and Ie*Re and duty cycle. Offline buck designs have improved over this and work in principle like active PFC to provide a sinusoidal (...)
A low voltage zener diode is a poor voltage regulator because its voltage changes with load current and with temperature changes. A zener diode wastes battery current all the time. Instead you should use a low dropout linear voltage regulator IC. The one I use is not made anymore but I still have some to use (...)
There are good reasons to stay with transformers and linear voltage regulators for your project. Using integrated voltage regulator ICs instead of discrete voltage regulator circuits with transistors, zener diodes etc. utilized in the original Moog devices can make the design a bit more convenient but (...)
1) Get rid of the resistor. Think about it. Say you've got 2000 volt spike; you'll have 18volts across your zener, 1982 volts across your resistor and 2000 volts into your regulator. 2) Get rid of the zener. Use a specially designed overvoltage device like a transorb (transient voltage suppressor). An ordinary (...)
zeners are not efficient nor stable compared to bandgap reference diodes used in all LDO's (LM317 type and many others) zeners must draw more than the worst case load to ensure when loaded there is still enough current to get past the knee in the zener. Then when no load, that current * voltage can lead (...)
Use the switching regulator or dc-dc charge pump convertor like MCP1252 etc. You can also use linear drop out regulator like LM series. zener diode will work too but heat dissipation will rise. But, if you are worried about the transient and spike protection, simply use metal oxide varistor or diode bypass circuit to power (...)
u have to add a current limiting resistor between diode and ground if u want to limit the current to zener and prevent overheating. Put the value of resistor which will not cross your zener max reverse current specification. If this zener diode is used for power supply, i suggest using switching (...)
Ambient temperature changes the base-emitter voltage of the transistor a little and changes the voltage of the zener diode a little. They work well between -55 degrees C or less to 150 degrees C or more. Of course if they have power dissipation then they heat themselves higher than the ambient temperature. Look at their datasheets to see.
There is no filter capacitor after the rectifier? 350W for the output is almost THIRTY amps! If you have a regulator why do you need a series zener based regulator?
not sure how you define 'best' mriad of ways: from LM317 to plain old series pass regulator with a zener diode. Or a voltage divider. Cheapest solution. and possibly worst solution.
Just cut the grounded terminal of R2 and connect it to the cathode of a 16 V zener diode and connect the anode to the ground.
you can vary the o/p by changing r2. zener also can be adopted as a reference & it will give you a very precise o/p
it will be a affordable to by a 9volt 500ma transformer rather than using any dc to dc converter use lm317 as a voltage regulator to get 3.3v or simply use a zener
Hi Steven, I clearly am not in the league with your other helpers, but here goes: 1 solution: use a zener diode and a resistor as a simple regulator, yes simple, yes there will be heat dissipated. To spread the heat(and current) set one up for each string. 2 solution: Use a transformer in your power supply. You (...)
Hi Corentin, It looks like the P6.5 high driver gets distroyed by an overvoltage spike. So somehow this spike must come in on the EN regulator line. If 30% gets distroyed after manufacturing may guess would be to check the tpye of D1 assembled maybe it is the wrong part? Protecting P6.5 by a series resistor and ot zener diode is another (...)
What about a resistor, transistor & zener diode?
A zener diode is the basic voltage regulator. It is capacitor-less. Many voltage regulator circuits use a zener diode. An internet search will turn up lots of articles and demonstrations. Also at the bottom of this webpage, see a list of related thread titles at this forum.
I "inherited" an e-bike (36V) without a battery charger. I need to build one as the price on a new one in my neck of the woods is totally ridiculous. My idea is to use a LM317 voltage regulator and boost the output by means of an 8V zener in the ADJ leg. I require a constant voltage of 45V with 1A MAX output. The charger will be built (...)
TV flyback transformers are designed to have voltages up to maybe 1KV on their primary sides and they should be driven at a frequency of around 15 - 16KHz to be efficient. The zener Diode regulator circuit is not suitable because it is designed to prevent too much current flowing through the zeners, in the Jacob's Ladder (...)
From the ADXL326 data sheet: current consumption 300uA ... I'd use a resitor (say 1.5k) followed by a zener diode (between 8 and 12V) and then 3V linear voltage regulator with typicalllly associated components such as input/output capacitors .. :wink: IanP
You certainly got it wrong! The zener must be connected between ground and the resistor from +12...+15 V to its other end (where you can get your 4V regulated) must be calculated from the DC current you want to draw to your load. Allow the zener to take some 50-100 mA to regulate. Calculate also the power loss for your resistor. Why people (...)
you can use zener Controlled Transistor Voltage regulator: zener Controlled Transistor Voltage regulators - Electronic Circuits and Diagram-Electronics Projects and Design
With 7805 or LM317 you get short circuit and overheat protection as a bonus (compared to the zener solution) Alex
For your need the steps should be as follows:- AC Mains-->Step Down--->Rectifier-->filter + regulator A zener diode can be used with AC source but the result is different from what you need. zener diodes are available in a wide variety of zener voltages and power ratings. The voltage range from less (...)
If you need 5 volts at the output, why do you have the zener and the 1n4007 after the 7805? Get rid of these two, and you should have your 5 volts.
hi i have dc voltage source change from 90 volt to 30 v dc i need to fix this voltage at 24 voltage dc so i search about voltage regulator such as LM78XX family but i found LM7824 and it has max input 40 volt, also i design zener circuit but i need to 2A in out out so we need to using resistor 120watt so it is not practical. i (...)
I think the basic point is to design a higher overvoltage margin. If you use TVS diodes, you have to look for the clamp rather than the breakdown voltage. A TVS that safely limits the voltage to 18V will have e.g. 13V breakdown voltage. Although there may be differences between types, you can expect a similar ratio for all TVS and zener diodes.
A voltage divider will be anything that divides the voltage , not just two resistors but also a zener , a transistor or anything that can be used in a linear voltage "regulator", all the designs are based an a pass element that introduces a voltage drop and keeps the output level to a constant level, this is based on a voltage divider. (...)
You can use an emitter follower and a zener diode File:Voltage stabiliser transistor.png - Wikipedia, the free encyclopedia or something more complex like Voltage regulator From Discrete Components but the resistor
zener diodes do not output a fixed voltage, as a voltage regulator IC would. They output a voltage, in your case around 12 volts, but it can be considerably higher or lower than exactly 12 volts. The actual voltage depends on: the dc current flowing thru the diode, the temperature, and manufacturing tolerances from diode to diode. You (...)
Use LM1117 or 3.3V zener diode. That should work
It can be done by driving the PNP via a 7V zener diode, as shown on the attached picture, or you can consider an optocoupler instead of the PNP+zener .. IanP :wink:
It is best to use a real regulator chip. The LM2941S can work down to a 0.5 volt differential Vout-Vin and still regulate, and provide 1 A. If you just want to hook up some parts lying around, a NPN transistor with the collector to battery V+, Base to battery V+ thru a say 1 K resistor, 4.3 V zener between ground (...)
I am designing a zener circuit, where in i am trying to use it as the regulator. The circuit contains the source supply and 3v3 zener diod is connected in series with Rs and i am running it in Reverse bias. The issue is i need to get vout=3.3v by varying my input source voltage from 0-12v. That (...)
You can consider linear regulator based on a power MOSFET, mounted on a reasonable heatsink, and set limits with resistors installed on top and bottom the main potentiometer .. see attached picture .. To provide basic regulation you can add a 150V zener diode (can consist of 3 x 47V, or 5 x 33V) and feed (...)
If regulation is not a big issue you can design very simple voltage regulator based only on a few components such as zener diode, NPN transistor and resistor .. see attached picture .. Details and discussion is at: Just keep in mind that the output voltage is roughly 0.65V lower than the zener
the TL2842 is good, use and calculate the input resistor (connected to VCC) ... the IC has an internal regulator, a zener diode. Look at the datasheet to calculate the power dissipated in the chip and you are good to go ! Why don`t you want an isolated output (using a transformator). By experience, start at 30V then go (...)
Hi Alex, sorry, but your circuit can not be a shunt regulator for 500mA! I don`t know so "high-power" zener diode they can work for that goal... Other them, that a zener has generel relative gross 5V only (usually in 20% range), exactly 5,1V and +/-10-20%. For 0.5A Load you must take some complexer circuits. You must (...)
original schematic is NOT a voltage regulator at all.. it is a voltage divider. i agree with FvM. another option is to use a 5.1V zener diode as your regulator but i don't know if that's any more efficient than the linear regulator. Mr.Cool
yes, a simple resistor-zener is ok but zener usually need a extra mask. and not all process support this device.
The reason is load regulation. the more current u draw from zener or TL431 u go away with the volatge u promise. But 74XX allow more current from them
I’m in the process of a similar conundrum. Mine is 90-140VAC in 12VDC-15VDC out 5mA. I considered a shunt and a discrete HV regulator but thought I’d run through a transformer less PSU. A couple of things one for 3V you definitely cant use a zener shunt. zeners have a very soft knee at that low a voltage given (...)
A standard forward biased power diode will act as a zener, should be around 5-600mv op. Just use as a zener, but other way round. Series resistor to suit circuit consumption.
the basic things which is needed for a power Supply are the bridge Rectifiers,the filers and the regulators. for filter we need an RC and for regulator we need a zener Diode.