In the simple zener regulators like the one below, If the load current is 1= 00ma and zener current is 10ma we calculate the resistor to allow...

In the simple zener regulators like the one below, If the load current is 1= 00ma and zener current is 10ma we calculate the resistor to allow 110ma. If Vin is above Vz and the load draws 50ma, the remaining 60ma flows throug= h zener. What makes it that the remaining current after the load current go= through the zener? Whay can't it be the otherway? i.e after the zener curr= ent the rema...

Hi, I need to protect the inout of the following DC to DC converter http://cds.linear.com/docs/Datasheet/3970fa.pdf I choose the...

Hi, I need to protect the inout of the following DC to DC converter http://cds.linear.com/docs/Datasheet/3970fa.pdf I choose the following zener diode http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=MAZ43900MFCT-ND I put the zener between the positive input and ground of the chip but as soon as I increase the DC voltage above 40 volts it get burned. Is the zener ...

Hello, If I had a little isolated 3.3V voltage regulator like this guy http://www.recom-power.com/pdf/Econoline/RM.pdf and I put a 3.3V...

Hello, If I had a little isolated 3.3V voltage regulator like this guy http://www.recom-power.com/pdf/Econoline/RM.pdf and I put a 3.3V zener right across the output to clamp the output to 3.3V like this zener http://www.diodes.com/datasheets/ds30410.pdf but I saw 3.6V across my zener.... any thoughts on what is going on? is it not cool to put a zener at the output to clamp the ...

I have an early version of a ham radio mobile supply that can't take more than 14.5 volts. Later versions used different transistors good to...

I have an early version of a ham radio mobile supply that can't take more than 14.5 volts. Later versions used different transistors good to 16v that sell for big $. Could I wire in a 14.something-small zener to a big power resistor to gnd - and if so would it cost less what size of zener and resistor would the panel suggest

Can a 1.5KE series TVS be used as a zener with a dC bias. Sat I have a circuit that is fed by a 50mA current source that on fault conditions...

Can a 1.5KE series TVS be used as a zener with a dC bias. Sat I have a circuit that is fed by a 50mA current source that on fault conditions pulses up to 500mA for ~10mS. The circuit needs to clamp at between 33 and 40V. I have a 36V 1.5KE already in the circuit for transient protection of a 30V line elsewhere but was wondering if I could use the same part for this zener application. ...

I need a 30V zener to drop the a high voltage of 100V down to 60V so I can use it with a switch mode power supply chip. So while this circuit...

I need a 30V zener to drop the a high voltage of 100V down to 60V so I can use it with a switch mode power supply chip. So while this circuit is in use the zener will be exposed to current pulses from the switching, these current pulses are in the neighborhood of 1A. I've gone to digikey and pulled up some zeners but I don't see this rating, where can I find the rating that tells me whether...

I was making a circuit that when you power it up with 5V a 5V LED indicator= turns on and if you power it up with 12V the 5V LED goes off and...

I was making a circuit that when you power it up with 5V a 5V LED indicator= turns on and if you power it up with 12V the 5V LED goes off and the 12V i= ndicator goes on. But... it's not coming on with 5V...=20 I spiced it, and it doesn't work in simulation either... if you look at the image on the link I put a 5.6V zener D1 in the circuit thinking that this Zener would be OFF = un...

So the following is the result of a previous thread where John Larkin suggested that one way to get rid of the voltage asymmetry in a...

So the following is the result of a previous thread where John Larkin suggested that one way to get rid of the voltage asymmetry in a Zener noise source was to sum a whole bunch together. I was initially doubtful, but thought I should do the experiment. I had a whole bunch (five) of lockins to test today. They have a build in Zener noise source with terrible asymmetry. So I summed them w...

Hi, DC to DC Converter:=20 http://cds.linear.com/docs/Datasheet/3970fb.pdf Zener...

Hi, DC to DC Converter:=20 http://cds.linear.com/docs/Datasheet/3970fb.pdf Zener Diode:=20 http://www.digikey.com/product-detail/en/1N5364B-TP/1N5364BTPMSCT-ND/111430= 6 The DC to DC converter can handle input voltage upto 40V. DC to DC convert= er is configured to output 5V. I do not want the input voltage to exceed 33= Volts. That is why I am using a 33V Zener. But I think that...

Zener noise source (freq < 1MHz.) I was revisiting Zener's as noise sources today. I first tried some 12V (1W*) diodes. (I want to bias them...

Zener noise source (freq < 1MHz.) I was revisiting Zener's as noise sources today. I first tried some 12V (1W*) diodes. (I want to bias them from 15V rails.) They worked fine, but I found the noise varied by at least 6dB (a factor of 2 in V peak) for different diodes from the same strip. (After testing 5 I gave up.) So I fell back to an old circuit. +15--+----+ Z | ^

I became discouraged of finding a suitable low-capacitance zener to protect the MOSFET gates in my high-voltage amplifier designs. (The...

I became discouraged of finding a suitable low-capacitance zener to protect the MOSFET gates in my high-voltage amplifier designs. (The protection may be optional, but one sleeps better with it in place.) Even the 50uA-rated low-current zener diodes are in fact larger-die types, with high capacitance. For example, the 7.5-volt MMSZ4693 has about 130pF at zero volts. My solution was to us...

Well I just blew out the G-S junction of a fet. I'm going to redesign circuit a bit... but I was also thinking of adding a ~15V G-S zener....

Well I just blew out the G-S junction of a fet. I'm going to redesign circuit a bit... but I was also thinking of adding a ~15V G-S zener. (V_GS max = +/- 20 V) Is there any downside I should think about? I guess I'd need some sort of current limit. (Resistor at a minimum) George H.

I know the theory, more or less. In practice, what's the reverse current through a zener diode at levels well below the breakdown voltage? ...

I know the theory, more or less. In practice, what's the reverse current through a zener diode at levels well below the breakdown voltage? I've got a circuit where I'm feeding a 12V linear regulator with a 25V line. It would be handy to put a zener diode in there so that when the 25V line drops to 4V the current into the regulator drops to tens of microamps. I'm wondering if a series...

Hi What is the minimum current for a zener, such as BZX55/C5V6 to work properly? I tried using 500uA, but it does not seem good. I looks like...

Hi What is the minimum current for a zener, such as BZX55/C5V6 to work properly? I tried using 500uA, but it does not seem good. I looks like less than 1mA is not enough, more like 2mA. Sonnich

Hi all, I have made a noise generator based on a zener diode. But I want to know how the noise reacts when I increase the current through de...

Hi all, I have made a noise generator based on a zener diode. But I want to know how the noise reacts when I increase the current through de zener diode. With PSpice a simulated the circuit and it seems when the current increased, sigma (RMS voltage) decreases.. But when I do the practical test, it seems when the current increased, sigma (RMS voltage) also increased.. Does anyone have...

Hi all, I just got done fixing a piece of apparatus that was returned to us. The thing was trashed, (all sorts of blown components) and I've been...

Hi all, I just got done fixing a piece of apparatus that was returned to us. The thing was trashed, (all sorts of blown components) and I've been trying to figure out what happened. Perhaps what I found weirdest is a power monitor LED. This sits across the +/-15 V rails, with a 12V zener and 5 k ohm resistor in series. (the zener stops it from turning on if one of the rails fails.) It j...

I was playing around with the CD4093 boost converter circuit someone posted a while back: What's the point in simulate, it's simple...

I was playing around with the CD4093 boost converter circuit someone posted a while back: What's the point in simulate, it's simple enough that I can just "simulate" on a breadboard. Related questions: there's some relation between the Zener quiescent current, the inductor DCR, max output current, and number of sec

This is my contributions to the already going thread on a 100 volt capable DC-DC buck boost using a 555 and a zener for regulation that uses the...

This is my contributions to the already going thread on a 100 volt capable DC-DC buck boost using a 555 and a zener for regulation that uses the minimum parts. I don't even have a timing cap in there. Set R1 for the Max I you need as the load and the zener will suck up what you don't use to maintain a constant voltage.. Of course this type of boost is only good if your load constraints ar...

Thought I'd zener some NPN b-e junctions. The mode is to use the collector and emitter, base open, putting a zenered e-b junction in series with...

Thought I'd zener some NPN b-e junctions. The mode is to use the collector and emitter, base open, putting a zenered e-b junction in series with the forward-biased c-b junction, "reference zener" style. BFT25 gives only 3.02 volts at 1 mA, with about 0.6 of that being c-b drop. BFS17 is 3.78, 0.53 of that c-b drop. Those are RF transistors. A more conventional BCX70 is 8.08 volts at...

Say one takes an E-B junction of a transistor or other diode and measures the (reverse) breakdown voltage over a wide range of currents...

Say one takes an E-B junction of a transistor or other diode and measures the (reverse) breakdown voltage over a wide range of currents (say 5nA to 5mA), and assume there is no point or range where one sees characteristics of negative resistance or of oscillation. Also say that voltage is about 9 volts. Q: is that zener or avalanche breakdown? Q: how does one make a SPICE mode...