Diode Equation needs a Knee Transplant

Started by jalb...@bsu.edu in sci.electronics.basics9 years ago 5 replies

I would like to know how to modify the diode equation: I = Io (Exp(eV/ NkT)-1) to work for a germanium diode. Using Io=10E-12,...

I would like to know how to modify the diode equation: I = Io (Exp(eV/ NkT)-1) to work for a germanium diode. Using Io=10E-12, e=1.602E-19, T=295, N=1, and k=1.380E-23 has the correct knee 0.6 for a silicon diode. What needs to be changed (or is there a new equation) to move the knee back to around 0.3 to model a germanium diode? Any help would be greatly appreciated. Thanks


Fast Recovery Diode

Started by Anand P. Paralkar in sci.electronics.basics7 years ago 3 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 Tunnel Diode Paradox

Started by jalb...@bsu.edu in sci.electronics.basics9 years ago 8 replies

Suppose that a tunnel diode wired in series with a load resistor is connected to a battery. The load resistor value is chosen so that...

Suppose that a tunnel diode wired in series with a load resistor is connected to a battery. The load resistor value is chosen so that the resistor load line passing through the negative resitance region of the tunnel diode will intersect the tunnel diode curve in three places. Which of the three current values will the tunnel diode choose and why? I am having a little trouble finding a...


Need info on diodes, 22pF and 100nF condensators

Started by Anonymous in sci.electronics.basics8 years ago 3 replies

In the process of acquiring parts for: http://usbirboy.sourceforge.net and trying to determine what type of diode is needed and where...

In the process of acquiring parts for: http://usbirboy.sourceforge.net and trying to determine what type of diode is needed and where to locate/purchase. I am a beginner at building these types of things. I am unsure if I need a full-wave rectifier (4 diodes) or half-wave (1 diode). Wondering if this diode is usable: 1N4004 400V 1A General Purpose Silicon Diode The defacto...


Basic Diode & Transisitor Question about Turn on Voltage

Started by TVisitor in sci.electronics.basics10 years ago 7 replies

Let's say I have a very simple circuit. +5V DC in series with a 100ohm resistor & diode (anode on the resistor, cathode to the - terminal of...

Let's say I have a very simple circuit. +5V DC in series with a 100ohm resistor & diode (anode on the resistor, cathode to the - terminal of supply. Diode forward voltage for turn on is 0.7V. I understand this circuit. The cathode is already grounded, so it's very easy to see that all you need is 0.7V on the anode of the diode to get it to turn on. Now, let's say you have the above ci...


1N2071 diode speed

Started by Anonymous in sci.electronics.basics9 years ago 7 replies

I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is an obsolete diode - Mouser doesn't carry it anymore. I looked up the...

I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is an obsolete diode - Mouser doesn't carry it anymore. I looked up the datasheet for the 1N2071. It seems designed to operate at 60 Hz, but didn't find any info on the maximum speed for how quickly the diode can operate. http://www.alldatasheet.com/datasheet-pdf/pdf/102157/IRF/1N2071.html Can the diode successfully op...


zener diode info and ID ?

Started by robb in sci.electronics.basics8 years ago 12 replies

i have a suspect zener diode from a PS . Zener, because the PCB says it is (ZD901) it looks like a small signal diode and it has a 16 and 2...

i have a suspect zener diode from a PS . Zener, because the PCB says it is (ZD901) it looks like a small signal diode and it has a 16 and 2 printed on opposite sides. to test/replace --- the 16 is for ? volts ? and the 2 is ? *OR* are the ###s short hand for some other 1N4### value ? and the best test is to measure V across it ? thanks for any helpful replies, robb


Trying to Find Class 1 Laser Diode

Started by Patty in sci.electronics.basics6 years ago 20 replies

I need to make a laser pointer for a profoundly disabled friend. It needs only to point 3 inches so I'm looking for a Class 1 laser diode that...

I need to make a laser pointer for a profoundly disabled friend. It needs only to point 3 inches so I'm looking for a Class 1 laser diode that will be safe for him despite his erratic movements. Any help in locating a Class 1 laser diode that would be appropriate would be REALLY appreciated. Thanks. Trish


PING: Kevin Aylward, Diode Model Question

Started by Jim Thompson in sci.electronics.basics3 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...


Need for inductive kickback diode

Started by Martin in sci.electronics.basics10 years ago 11 replies

If you are using PWM to control the brightness of an incandescent light, should you use an inductive kickback diode to protect...

If you are using PWM to control the brightness of an incandescent light, should you use an inductive kickback diode to protect the transistor? It is of course recommended to use when you are driving coils, relays, motors, etc. A light is a coil, althought I would guess the inductance is pretty low. Would good practice be to put the diode in "just in case", or its absolutely unneeded?...


1N5817 schottky

Started by John in sci.electronics.basics9 years ago 8 replies

Hello, I'm about to make a wideband rf sniffer using an op amp and a simple detector front end feeding a capacitor and one of the inputs to...

Hello, I'm about to make a wideband rf sniffer using an op amp and a simple detector front end feeding a capacitor and one of the inputs to the op amp. I could bias the diode near conduction if it will help. I have to hand a 1n5817 schottky diode which is claimed to have a low forward voltage drop. While it's not exactly a signal diode will it do the job? Our local electronics store (Map...


Diode Lead Length

Started by Anand P. Paralkar in sci.electronics.basics4 years ago 9 replies

Hi, I would like to use the 1N5283 diode in a certain application. Like some other applications in power electronics, this diode datasheet...

Hi, I would like to use the 1N5283 diode in a certain application. Like some other applications in power electronics, this diode datasheet too mentions a certain Lead Length to be maintained. (See http://www.datasheetcatalog.org/datasheet/motorola/1N5298.pdf) Could someone please explain this? Why does this distance have to be maintained? (Its got to do with the thermal character...


Microwave diode?

Started by DaveC in sci.electronics.basics9 years ago 22 replies

Have simple detector circuit that specifies 1N21B diode. That diode is 20-plus years old and obsolete. Looking for current equivalent, possibly...

Have simple detector circuit that specifies 1N21B diode. That diode is 20-plus years old and obsolete. Looking for current equivalent, possibly (but not necessarily) smt. Are these useable in place of a 1N21B for 2.4 GHz detection?: Suggestions welcome. Thanks, -- DaveC me@bogusdomain.net This is an invalid return add


diode sense for temperature

Started by HapticZ in sci.electronics.basics10 years ago 11 replies

would it be usefull to use two similar 1n4148 diodes to sense air tempreature differential? my application is to use one diode at floor level...

would it be usefull to use two similar 1n4148 diodes to sense air tempreature differential? my application is to use one diode at floor level and another diode at ceiling level to detect gross temperature differences and then turn on a fan if the difference is too great. (high celings are architecturally trendy, but bad for effective heat usage, might be cheaper to use radiant after all!...


reliably testing diodes in circuit ?

Started by robb in sci.electronics.basics10 years ago 11 replies

while checking diodes **in circuit** with diode setting on DMM i ran across a unexpected results where diode test at (.567 V) in one direction...

while checking diodes **in circuit** with diode setting on DMM i ran across a unexpected results where diode test at (.567 V) in one direction then swap probes around and expect (0 V) but i get unexpected (1.897 V) reading. are there conditions where this is a valid reading that does not indicate a circuit error or fault with diode? thanks, robb


TTL input circuit to drive diode

Started by Gary H in sci.electronics.basics11 years ago 5 replies

Hi. I need a little help with something that should be pretty basic. I have a control board that has a TTL output to turn on and off a laser. ...

Hi. I need a little help with something that should be pretty basic. I have a control board that has a TTL output to turn on and off a laser. The laser is nothing more than a diode that consumes about 60mA. So, I want to be able to turn the diode on or off with the TTL output. I don't really know much about TTL requirements. But, would a NPN transistor with resistor between the bas...


zener diode question, minimum current?

Started by panfilero in sci.electronics.basics8 years ago 10 replies

Hello, I want to use a zener diode as a voltage clamp, and I'm wondering how to bias it.... I'm getting a small signal TZX3V0A diode, according...

Hello, I want to use a zener diode as a voltage clamp, and I'm wondering how to bias it.... I'm getting a small signal TZX3V0A diode, according to their datasheet, their test current is 5mA.... ok that's fine, I can get a resistor value to limit my current to that... but, is that the spec I should follow... the 5mA test current? My concern is that I don't want to be too low and too close to ...


sizing a freewheeling diode for a coil

Started by Matt in sci.electronics.basics10 years ago 38 replies

I am controlling the coil of a relay using a switching transistor. To protect the transistor I intend to use a freewheeling diode in parallel...

I am controlling the coil of a relay using a switching transistor. To protect the transistor I intend to use a freewheeling diode in parallel with the coil. I'm not sure of the issues in specifying the diode. My impulse is to simply use a 1N4007 http://www.fairchildsemi.com/pf/1N/1N4007.html (1000V peak repetitive reverse voltage, 1.0A average rectified forward current) because it is ...


confusion on diode polarity

Started by rabiticide in sci.electronics.basics9 years ago 25 replies

I'm trying to make a basic circuit with a diode. Had it not been marked "cathode/anode" I would have not been confused - I would've just had the...

I'm trying to make a basic circuit with a diode. Had it not been marked "cathode/anode" I would have not been confused - I would've just had the electrons follow the arrow. But the arrow points away from the anode and towards the cathode, and this is the opposite of what I'd expect. What does "cathode" and "anode" mean on a diode? To have the electrons flow with the arrow my "anode" will b...


Schottky-barrier diode and frequency performance

Started by karthikbalaguru in sci.electronics.basics10 years ago 3 replies

Hi, How can a Schottky-barrier diode enhance frequency performance ? Can someone here kindly provide me with some link or document that talks...

Hi, How can a Schottky-barrier diode enhance frequency performance ? Can someone here kindly provide me with some link or document that talks in detail about Schottky-barrier diode's relation with frequency performance. Thx in advans, Karthik Balaguru