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.basics5 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


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...


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 ...


pin diode

Started by Anonymous in sci.electronics.basics2 years ago 8 replies

Hi, What is the difference between Light Detector Resistor and a pin diode? And which one is better to use for solar tracking purposes and...

Hi, What is the difference between Light Detector Resistor and a pin diode? And which one is better to use for solar tracking purposes and why? For example LDR: http://www.digikey.com/product-detail/en/PDV-P8104/PDV-P8104-ND/480611 PIN DIODE: http://media.digikey.com/pdf/Data%20Sheets/Everlight%20PDFs/PD204-6C.pdf mel


diode, rectifier dead?

Started by Anonymous in sci.electronics.basics9 years ago 12 replies

Can anyone confirm whether following microwave oven components are dead -diode hvr1x8019:tested with analog ohm meter-short both...

Can anyone confirm whether following microwave oven components are dead -diode hvr1x8019:tested with analog ohm meter-short both directions -rectifier 2x062h 8025:..open in both directions tnx


Inductor current can't be suddenly cutoff if no freewheel diode is attached

Started by Patrick Chung in sci.electronics.basics4 years ago 3 replies

Inductor current can't be suddenly cutoff if no freewheel diode is attached. New tutorial...

Inductor current can't be suddenly cutoff if no freewheel diode is attached. New tutorial is ready http://www.cirvirlab.com/index.php/tutorials/105-r-l-circuit-with-mosfet-as-switch-and-freewheel -diode.html and online simulation http://www.cirvirlab.com/simulation/r-l_circuit_with_mosfet_as_switch_and_freewheel_diode.php


power diode testing?

Started by mynick in sci.electronics.basics7 years ago 6 replies

Tested each of diode pair fch20u10 with analog ohm-meter: directly-open but with bigger direct voltage conducts, inversely- resistance of 40...

Tested each of diode pair fch20u10 with analog ohm-meter: directly-open but with bigger direct voltage conducts, inversely- resistance of 40 ohms! but I suspect it is ok or not because tested an ok mur1620 and it showed 100ohms I guess those fast power diodes should not show inverse resistance of Kohms?


model parameters in LT Spice

Started by Michael Robinson in sci.electronics.basics7 years ago 19 replies

I've just started using the free version of LT Spice and haven't had a problem doing simulations as long as the components are in the library. ...

I've just started using the free version of LT Spice and haven't had a problem doing simulations as long as the components are in the library. Now I need to do a simulation using a component that's not in the LT Spice library, the 1N4001 diode. Somebody sent me the model for the 1N4001, which is great. So my question is, after you put a diode symbol in the schematic, how do you assign...


schottky diode question

Started by tempus fugit in sci.electronics.basics8 years ago 10 replies

Hey all; I'm planning on using a MAX4622 CMOS switch in a circuit I'm building. On p.7 of the data...

Hey all; I'm planning on using a MAX4622 CMOS switch in a circuit I'm building. On p.7 of the data sheet (http://datasheets.maxim-ic.com/en/ds/MAX4621-MAX4623.pdf), it says: "If power-supply sequencing is not possible, add two small signal diodes in series with the supply pins and a Schottky diode between V+ and VL" I've read a bit about Schottky diodes, and I see that there are severa...


diodes, ideal diode equation, and temperature coefficients

Started by kell in sci.electronics.basics11 years ago 4 replies

The ideal diode equation seems to predict that for a given current there will be a fixed ratio between temperature and voltage. I took some...

The ideal diode equation seems to predict that for a given current there will be a fixed ratio between temperature and voltage. I took some measurements and worked out the equation for several diodes, and also plotted the values on graph paper. For all of the diodes I tried, 1N4003, 1N4148, two shottkys 1N5818 and MBR3035PT, and a red led, I got a nice straight line when I graphed 8 or so d...


Types of diode-connected BJTs

Started by C Egernet in sci.electronics.basics7 years ago 19 replies

What are the relative merits of diode-connecting a BJT by shorting base and collector (using B-E junction) versus shorting base and emitter (C-B...

What are the relative merits of diode-connecting a BJT by shorting base and collector (using B-E junction) versus shorting base and emitter (C-B junction)? Na=EFvely, I have assumed that one always uses the B-E junction but then I saw this post from s.e.d by Phil Hobbs: > BFT25A C-B junctions are at least as good as 2N4117As as diodes. > > Cheers > > Phil Hobbs What gives? Chr


LEDs intensity solutions?

Started by Vlad in sci.electronics.basics10 years ago 8 replies

Which one of these three solutions is the best for the best light intensity? http://img329.imageshack.us/img329/5950/solucijenw2.jpg More...

Which one of these three solutions is the best for the best light intensity? http://img329.imageshack.us/img329/5950/solucijenw2.jpg More info: source voltage - 12V diode forward voltage - 3.7V diode forward current - 20mA number of LEDs - 23 (blue, 470nm)


A capacitor/resistor question

Started by Anonymous in sci.electronics.basics4 years ago 2 replies

Greetings All, In the book "Electric Motors and Control Techniques" a circuit is illustrated that is for the dynamic braking of a squirrel cage...

Greetings All, In the book "Electric Motors and Control Techniques" a circuit is illustrated that is for the dynamic braking of a squirrel cage motor. This circuit discharges a capacitor through the field windings to slow the motor. The capacitor is connected across the AC power to the motor in series with a 50k resistor and a diode. I under stand why the diode is there. The resistor must be...


Re: Automotive alternator windings & rectifier

Started by Mike Cook in sci.electronics.basics4 years ago 4 replies

> > http://www.autoshop101.com/forms/alt_bwoh.pdf > > > > has photos of an alternator with 4 connections for windings (each of 3 > > ...

> > http://www.autoshop101.com/forms/alt_bwoh.pdf > > > > has photos of an alternator with 4 connections for windings (each of 3 > > phases + common), > > Not one of the pages shows four connections brought out from the > windings. Photo on p. 18. > > and the 8 diode rectifier. > > I don't see any 8 diode rectifier. Photo on p. 25. Note callouts for 6 diodes but you can see 8 round