Is this just diode noise?

Started by amdx in sci.electronics.design2 years ago 3 replies

Hi all, I'm working on a circuit to test LC ferrite antennas. I found the amp output very noisy with the rectifying diode in the circuit. I can...

Hi all, I'm working on a circuit to test LC ferrite antennas. I found the amp output very noisy with the rectifying diode in the circuit. I can hear the noise and measure it on my meter. Very little noise without the diode. See the link below for a block drawing of the circuit with and without the diode. > http://theradioboard.com/rb/download/file.php?id=4374 Is it simply the diode noi


reverse biased diode variable resistance experiment

Started by Jamie M in sci.electronics.design4 years ago 15 replies

Hi, This is related to the "poor mans superconductor wire" thread, for testing an idea of anomalous resistance decrease in a diode. If you...

Hi, This is related to the "poor mans superconductor wire" thread, for testing an idea of anomalous resistance decrease in a diode. If you reverse bias a diode, then electrons move closer to the junction of the diode as the voltage pressure increases. I was thinking maybe this biasing of the electric field will change the electrical resistance on each side of the diode. Ie. if the actu...


Fast Recovery Diode

Started by Anand P. Paralkar in sci.electronics.design7 years ago 11 replies

Hi Everybody, Could someone please explain the use of a Fast Recovery Diode? I am particularly interested in: 1. How is this diode...

Hi Everybody, Could someone please explain the use of a Fast Recovery Diode? I am particularly interested in: 1. How is this diode different from a regular rectifier diode. 2. The role of these diodes in MOSFET circuits. (Sorry, there is no Wiki for this.) Thanks for your help. Regards, Anand


Diode + Diode Zener and Inductive load

Started by Bicio in sci.electronics.design9 years ago 8 replies

I know that inserting a normal diode in parallel to a inductor is usefull for preventing voltage spikes when the current drop to zero (for...

I know that inserting a normal diode in parallel to a inductor is usefull for preventing voltage spikes when the current drop to zero (for example due to a transistor). So, with a diode, the inductor discharge itself with a time constant of L/R. With a Zener in series to a diode, the inductor discharge faster because of the higher inverse voltage. But, how can I translate this effect in mat...


A diode in series with a brushed universal motor?

Started by John Doe in sci.electronics.design3 years ago 5 replies

Not concerned about safety for this discussion. What will happen if you put a diode in series with a universal brushed motor? Of course...

Not concerned about safety for this discussion. What will happen if you put a diode in series with a universal brushed motor? Of course talking about a diode that can handle standard USA 120 V 60 Hz household power. Just putting a diode on one of the wires coming from the outlet, to rectify the current. Would a capacitor after the diode be useful? What sort of capacitor would be require...


Matched diodes

Started by Raveninghorde in sci.electronics.design7 years ago 17 replies

I want to clamp a 10mV signal to 0V. A matched common anode diode would do it with 1 diode fed from a positive supply so that the anode was a...

I want to clamp a 10mV signal to 0V. A matched common anode diode would do it with 1 diode fed from a positive supply so that the anode was a diode drop above 0V and the other diode clamping to this point. Easy in principle. I looked at some specs such as BAT54A, and various other parts but so far I haven't found a part which specifies the matching of Vf. Any suggestions?


Wrong packaged diode

Started by djj08230 in sci.electronics.design8 years ago 3 replies

Hello all, A board we produce has a battery that power a static RAM through a diode. This is a SMD package, maybe a SMA, but can't say for...

Hello all, A board we produce has a battery that power a static RAM through a diode. This is a SMD package, maybe a SMA, but can't say for sure right now. We have had a few problems with the battery circuit, that I know have been solved changing the diode. I have seen only one of those myself, and it looks like the diode is packaged the other way round i.e. the package strip pointing ...


Electrochemistry in diodes?!

Started by Paul in sci.electronics.design9 years ago 4 replies

Hi, I'm doing some diode research, and would like to know of any possible DC voltages produced in the diode due to electrochemical...

Hi, I'm doing some diode research, and would like to know of any possible DC voltages produced in the diode due to electrochemical reactions. It's a palladium-silicide diode, part number SMS7630, but also has gold. Over time the atoms could migrate. The SMS7630 is a microwave diode used for small signals. It is not terribly uncommon for the DC voltages produced by small AC signal rectifica...


Simple Circuit question

Started by Ivan Vegvary in sci.electronics.design11 months ago 15 replies

Doing self study. Diode circuit. 10V battery followed by series load resistor. Thence a resistor and diode in parallel and back to the...

Doing self study. Diode circuit. 10V battery followed by series load resistor. Thence a resistor and diode in parallel and back to the battery. Simple to take the 0.7v drop of the diode and have 9.3V remaining on across the first resistor. This allows calculation of total current through circuit and the rest is easy. BUT Then they want you to use the "ideal diode" method to solve same problem....


How long does it take for a diode to conduct?

Started by Tim Wescott in sci.electronics.design5 years ago 79 replies

Is it reasonable to expect that the turn-on (not off -- _on_) time of a diode should be pretty much consistent with the inductance of the...

Is it reasonable to expect that the turn-on (not off -- _on_) time of a diode should be pretty much consistent with the inductance of the package, and not much else? A customer just sent me some O-scope traces of a circuit where a voltage at a catch diode anode is (at least apparently) going several hundred volts above its cathode for a microsecond before settling out to the nominal a...


diode recovered charge

Started by John Larkin in sci.electronics.design3 years ago 57 replies

I got curious about the amount of reverse-recovery charge in PN diodes, as a function of forward current (and time of fwd bias) and diode...

I got curious about the amount of reverse-recovery charge in PN diodes, as a function of forward current (and time of fwd bias) and diode size/type. Question is, are the LT Spice diode models realistic? We'll have to test some diodes to see. Since diode recovery for a given part number depends a lot on the manufacturer, we should stick to sole-source parts and tweak the Spice model to al...


Substitute diode for FES08AT

Started by Daku in sci.electronics.design6 years ago 2 replies

Could some electronics guru suggest a substitute diode for the signal diode FES08AT ? Any hints, suggestions would be immensely helpful . Thanks...

Could some electronics guru suggest a substitute diode for the signal diode FES08AT ? Any hints, suggestions would be immensely helpful . Thanks in advance.


Diode Laser

Started by Jon Slaughter in sci.electronics.design8 years ago 20 replies

What does a diode laser module add to a diode laser? A voltage regulator or current limiter?

What does a diode laser module add to a diode laser? A voltage regulator or current limiter?


LT Spice ideal diode

Started by John Larkin in sci.electronics.design7 years ago 11 replies

I recall somewhere, maybe in this ng, the procedure for making an ideal diode in LT Spice. But I can't find it now. Help! The ideal diode...

I recall somewhere, maybe in this ng, the procedure for making an ideal diode in LT Spice. But I can't find it now. Help! The ideal diode should be a stock pulldown part. I wonder why it's not. And why can't I change the voltage of one of their pull-from-the-list zeners? That would sure be convenient. John


reverse voltage protection with parallel diode

Started by Anonymous in sci.electronics.design5 years ago 11 replies

I have a diode 1N5402 connected in parallel reverse biased across the power= supply for reverse polarity protection. The maximum absolute...

I have a diode 1N5402 connected in parallel reverse biased across the power= supply for reverse polarity protection. The maximum absolute ratings of t= he load IC says -0.3V to +30V. If reverse power is applied, anything above = diode's forward drop it will short circuit and break the fuse. No issue her= e. If, let's say, 0.5V is applied in reverse, the diode will not conduct an= d reverse ...


TEC for laser diode

Started by mt in sci.electronics.design4 years ago 26 replies

I have a laser diode that is cooled by a fan and a heat sink. I have a small TEC lying around and I would like to integrate that to the laser...

I have a laser diode that is cooled by a fan and a heat sink. I have a small TEC lying around and I would like to integrate that to the laser diode head. How do I go about controlling the voltage supply to maintain a stable temperature. Thanks for you valuable input


Schottky diodes

Started by Raveninghorde in sci.electronics.design7 years ago 15 replies

I am working on a 5A buck converter. About 50% of the losses are due to the schottky diode a 50WQ10FNPbF. So I am lookinig to optimize...

I am working on a 5A buck converter. About 50% of the losses are due to the schottky diode a 50WQ10FNPbF. So I am lookinig to optimize the diode. Looking at the specs I am looking to use a dual 15A part, Sanyo SBT150-06J. I've chosen this because it has the lowest forward voltage I can find. The best efficiency comes from using the diode near it's maximum junction temperature. Allowing...


bandgap

Started by Michael Robinson in sci.electronics.design7 years ago 8 replies

Vbe has kind of mystified me for a long time. I finally dove into a good textbook and picked apart the equations. This is actually the math...

Vbe has kind of mystified me for a long time. I finally dove into a good textbook and picked apart the equations. This is actually the math for a bjt (diode-connected), and it has a term related to base doping level, so it may not apply to a diode that consists of a single pn junction. But that's just as well; it makes more sense in most applications to use a diode-connected transist...


Flyback output diode peak curent vs average current

Started by Mook Johnson in sci.electronics.design9 years ago 3 replies

In a DCM flyback with its high peak to average current ratio. When sizing a diode do you rate thediode for the maximum peak current. I have a...

In a DCM flyback with its high peak to average current ratio. When sizing a diode do you rate thediode for the maximum peak current. I have a 2A average current with 12A peaks at the start of the flyback. Repeats every 5uS. Which current rating should I look for in the diode? 3A? 6A? 15A? All of this makes a difference in the size of the diode package which I'm trying to minimize...


LT Spice Question

Started by John Larkin in sci.electronics.design7 years ago 42 replies

If I plop a 1N4148 onto a schematic, from the standard parts library, how can I change Is? There's no obvious (to me) way to do this. I...

If I plop a 1N4148 onto a schematic, from the standard parts library, how can I change Is? There's no obvious (to me) way to do this. I can see the model parameters in the diode selection box, but I can't edit or even copy them, so if I want to make my own diode model Spice directive, I have to read and type all that stuff manually. Seems silly. Are the diode params in some file some...