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


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...


Simple Circuit question

Started by Ivan Vegvary in sci.electronics.design1 year 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.design6 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...


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.design8 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


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...


PING: Kevin Aylward, Diode Model Question

Started by Jim Thompson in sci.electronics.design3 years ago 8 replies

Hi Kevin, Suppose I wanted to model JUST the capacitance portion of a diode? No DC current, etc. The equation "fold-over" at VD~FC*VJ...

Hi Kevin, Suppose I wanted to model JUST the capacitance portion of a diode? No DC current, etc. The equation "fold-over" at VD~FC*VJ looks to be PITA to implement. Maybe you know of a way to trick a full diode model into not doing its DC thing ?:-} ...Jim Thompson -- | James E.Thompson | mens | | A...


"reverse diode"

Started by jon....@gmail.com in sci.electronics.design5 years ago 38 replies

Is there a passive device similar to a diode that has low impedance at 0 fo= rward voltage and high impedance at some larger voltage? e.g.,...

Is there a passive device similar to a diode that has low impedance at 0 fo= rward voltage and high impedance at some larger voltage? e.g., flip the diode curve horizontally then center the knee of the several= hundred mV above 0V. One can emulate such a device a number of ways more or less but can one be = made based on fundamental physical principles so that it behaves very simil= ar ...


Super Diodes and detectors

Started by Graeme Zimmer in sci.electronics.design7 years ago 8 replies

Hi, This post was prompted by the recent discussion about Diode-Connected Transistors. The Crystal Set nutters are always seeking the holy...

Hi, This post was prompted by the recent discussion about Diode-Connected Transistors. The Crystal Set nutters are always seeking the holy grail of a perfect diode detector (it must be passive of course). The problem is that existing diodes are lousy rectifiers at low currents (three steps forward and two steps back). What is needed is a diode which has a steep forward/reverse c...


Hot-carrier diode substitute

Started by garyr in sci.electronics.design4 years ago 12 replies

I want to make a simple rectifier for an RF signal, frequency less than 10 MHz. The schematic below (view with fixed font) is from an...

I want to make a simple rectifier for an RF signal, frequency less than 10 MHz. The schematic below (view with fixed font) is from an article describing a circuit useable with much higher frequencies and used a hot-carrier diode (1N5711). For relative low frequencies would a general purpose diode such as a 1N4148 be adequate? If a hot-carrier would be necessary I have a problem because I do...


Rectifier Schottkies in parallel

Started by Piotr Wyderski in sci.electronics.design3 years ago 22 replies

Hello, many Schottky rectifier diodes contain two diodes within a single package, usually with the cathodes connected. Does it make sense to...

Hello, many Schottky rectifier diodes contain two diodes within a single package, usually with the cathodes connected. Does it make sense to connect the anodes too in order to get a diode which can withstand higher current? Is a 2x30A diode more or less equivalent to a single 60A diode? I am thinking of VBT6045CBP if it helps. The application: a high-current 50Hz rectifier. Best r...


Sampler diodes with more barrier height?

Started by Joerg in sci.electronics.design4 years ago 100 replies

Folks, After John Larkin sent me SMS7621 Schottky RF diodes I played around with them in the lab. While they perform nicely at room...

Folks, After John Larkin sent me SMS7621 Schottky RF diodes I played around with them in the lab. While they perform nicely at room temperature everything goes to pots at a slightly elevated temperature. At ballpark 50C the leakage current is already painfully high for use as a sampler diode. Question: Is there a fast RF diode or sampling diode in a reasonable cost range (low single-dig...


Collector-Base diode of BJT as an Ultra low leakage protection diode

Started by Ebrahim in sci.electronics.design8 years ago 2 replies

Hello, I want to know, is there anyone here that has used a BJT instead of an ultra low leakage diode(

Hello, I want to know, is there anyone here that has used a BJT instead of an ultra low leakage diode(


Next: The tunnel diode oscillator.

Started by Jan Panteltje in sci.electronics.design4 years ago 33 replies

Next: The tunnel diode oscillator. Given an LC wit some Q (read damping), if we can neutralize that R, would it start swinging all by...

Next: The tunnel diode oscillator. Given an LC wit some Q (read damping), if we can neutralize that R, would it start swinging all by itself? Well how do you neutralize a resistor? Simple: put a negative resistor in series or parallel with it. Mr Esaki invented the tunnel diode many years ago, it has, at some point, a negative slope in its I versus U curve. So use a properly biased...