Negative resistance with BJTs

Started by Anonymous in sci.electronics.design4 years ago 54 replies

a four layer diode, consisting of alternate p, n layers acts as a negative resistance, and can be realized in practice with a pair of NPN and...

a four layer diode, consisting of alternate p, n layers acts as a negative resistance, and can be realized in practice with a pair of NPN and PNP transistors, connected in specific ways. Now, is it possible to achive this a series connection of two discrete diodes ? I was just thinking about it.


OpAmp Voter

Started by SRob...@SpamSucks.net in sci.electronics.design8 years ago 32 replies

I have three DC-5Khz, 0-5 V positive going signals. I'd like to select and = pass the highest of the signals, without diode losses. Using a...

I have three DC-5Khz, 0-5 V positive going signals. I'd like to select and = pass the highest of the signals, without diode losses. Using a microproces= sor is out of the question. Cost is a object and actives should be limited= to devices that can be second sourced.=20 This is for converting a RGB command signal to an intensity signal. Steve=20 =20


Is there an affordable UV photodiode?

Started by LM in sci.electronics.design10 years ago 16 replies

While reading posts about photodiodes and counting photons I noticed that the topic is more than interesting, it could be useful. I have a use...

While reading posts about photodiodes and counting photons I noticed that the topic is more than interesting, it could be useful. I have a use to an affordable photodiode which is sensitive at around 300 =96 100 nm. This is not for space craft or scientific instrument so price is important. By the way, if you are going to answer "yes" to my topic, please tell the name of the diode or its...


Baud rate with LED & Phototransistor (or diode)

Started by Tim Wescott in sci.electronics.design8 years ago 32 replies

I need to make a device that's totally sealed, but is powered by, and communicates with, the outside world. For communications, I'm thinking...

I need to make a device that's totally sealed, but is powered by, and communicates with, the outside world. For communications, I'm thinking along the lines of embedding IR LEDs and phototransistors in the boards, and talking that way. Alignment in the z direction should be easy -- that can be achieved by two flat plates that touch. Alignment in the x and y directions would be super...


Ta Da!

Started by Jim Thompson in sci.electronics.design8 years ago 6 replies

Ta Da! Title of Invention: METHODS SYSTEMS AND DEVICES FOR MINIMIZING POWER LOSSES IN LIGHT EMITTING DIODE DRIVERS Filing Date: May 28,...

Ta Da! Title of Invention: METHODS SYSTEMS AND DEVICES FOR MINIMIZING POWER LOSSES IN LIGHT EMITTING DIODE DRIVERS Filing Date: May 28, 2014 ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Sys...


The tunnel diode is back, as TeraHertz oscillator

Started by Jan Panteltje in sci.electronics.design5 months ago 11 replies

Terahertz radiation source: Compact and simple: https://www.sciencedaily.com/releases/2022/01/220111112018.htm paper: ...

Terahertz radiation source: Compact and simple: https://www.sciencedaily.com/releases/2022/01/220111112018.htm paper: https://aip.scitation.org/doi/10.1063/5.0068114 Interesting on chip construction


Nice Small HV-ish Diode

Started by Tim Williams in sci.electronics.design5 years ago 17 replies

https://industrial.panasonic.com/content/data/SC/ds/ds4/DA2JF8100L_E.pdf 800V, 200mA, 0.6pF @ 0V, 10ns, SOD-323F Tim -- Seven Transistor...

https://industrial.panasonic.com/content/data/SC/ds/ds4/DA2JF8100L_E.pdf 800V, 200mA, 0.6pF @ 0V, 10ns, SOD-323F Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: https://www.seventransistorlabs.com/


ephemt as diode

Started by John Larkin in sci.electronics.design6 years ago 84 replies

I had an ephemt on the bench and some test gear handy, so I played with it a bit. This is...

I had an ephemt on the bench and some test gear handy, so I played with it a bit. This is cool: https://dl.dropboxusercontent.com/u/53724080/Parts/Fets/Ephemt_Diode.JPG These are "RF" parts, so the data sheets and appnotes say very little about DC behavior. There must be a use for this, somewhere. -- John Larkin Highland Technology, Inc picosecond timing precision me...


large (~9mm square) bare photo diode vendors.

Started by George Herold in sci.electronics.design6 years ago 21 replies

When we first bought these (from advanced photonics) they were less than...

When we first bought these (from advanced photonics) they were less than $10. http://www.digikey.com/product-detail/en/PDB-C613-2/PDB-C613-2-ND/201831 Now they are Luna optoelectronics... price continues to rise. It's hard to know when you should start looking for a new vendor. George H.


oven heated diode.

Started by Jamie in sci.electronics.design9 years ago 12 replies

Has any one ever applied oven heated diodes in a circuit to keep the Vf down to a minimum? I remember years ago I was tossing this idea...

Has any one ever applied oven heated diodes in a circuit to keep the Vf down to a minimum? I remember years ago I was tossing this idea around in my head but didn't have the resources to experiment with this idea. Thinking a glass type package may live longer. Jamie


Power supply topology question ...

Started by Anonymous in sci.electronics.design9 years ago 18 replies

Could some electronics guru please shed some light on the following. The standard topology for a linear regulated power supply is basically...

Could some electronics guru please shed some light on the following. The standard topology for a linear regulated power supply is basically as follows: isolation step-down transformer | v rectifier(bridge or 2 - diode) | v capacitor ripple filter bank | v voltage regulator ...


Diode and capacitor on mains input

Started by Anonymous in sci.electronics.design7 years ago 11 replies

I'm fixing a B & O amplifier, a pleasure due to the clear schematics supplied with it but do not understand one little area. In series with the...

I'm fixing a B & O amplifier, a pleasure due to the clear schematics supplied with it but do not understand one little area. In series with the mains input there is an electrolytic and a pair of back to back diodes all in parallel. What is this for ? Excuse the poor ASCII art. ---| |--- | | ---||--- Jon


Diode Vf / Temp

Started by Anonymous in sci.electronics.design4 years ago 5 replies

Used what I had, about probably 1,000 PIV bridge looks from the size of it good for 4 amps. I'm using it for 12 volts at about 2.12 amps. Seems to...

Used what I had, about probably 1,000 PIV bridge looks from the size of it good for 4 amps. I'm using it for 12 volts at about 2.12 amps. Seems to get a bit warm. So I sticks my dandy new meat thermometer on it which might not be quite traceable to NIST and it says 70C after a couple of hours running. A couple hours later it is up to around 80C. Maybe we can live at 80C. I checke


Split control loop

Started by George Herold in sci.electronics.design5 years ago

Hi all, (as is usual) I think I figured this out in the process of asking you a question. But I welcome any input or comments. First a bit...

Hi all, (as is usual) I think I figured this out in the process of asking you a question. But I welcome any input or comments. First a bit of background. I made the laser diode controller ~10 years ago. I added this section so that you could side lock to one of the absorption features. Input signal is low pass filtered(single pole), DC offset, maybe some gain and then sent to the pi...


Recommend a CAD program please.

Started by Geoffrey S. Mendelson in sci.electronics.design7 years ago 30 replies

I need to draw some simple schematics. 5 to 10 components. Long ago I did them with MacDraw. 30 years later I am looking for something as...

I need to draw some simple schematics. 5 to 10 components. Long ago I did them with MacDraw. 30 years later I am looking for something as simple, runs under windows and has a library of common components (resitor, capacitor, transistor, diode, fuse). In short something with not much of learning curve that will do the job. Does not need to do PCB layout, circuit analysis, etc. It does ...


fast(ish) one-shot

Started by George Herold in sci.electronics.design4 years ago 30 replies

So I'm making a one shot out of two 74HC14, the first gives a nice sharp edge to drive the cap. (~47pF) into the second. (which has R and diode...

So I'm making a one shot out of two 74HC14, the first gives a nice sharp edge to drive the cap. (~47pF) into the second. (which has R and diode to positive rail. I think R_min is 500 ohm. Well, that's more delay than I thought it was, (eating crow.. "mmm good crow") I've got a faster comparator to try on the front end, maybe I should do that first.? George H.


diode leakage tester

Started by John Larkin in sci.electronics.design4 years ago 21 replies

I was driving home over Bernal Heights, full of pretty much legal amounts of Vietnamese food and beer, when this popped into my head for no...

I was driving home over Bernal Heights, full of pretty much legal amounts of Vietnamese food and beer, when this popped into my head for no reason: https://www.dropbox.com/s/d8j2sus66s4w8ok/Diode_Leak_5.JPG?dl=0 It's feasible down to the hundreds of fA maybe. Any fA measurement will be slow. The idea here to integrate the current into a good cap, and use the DUT itself as the samplin...


LTspice Zener Models

Started by Rick C in sci.electronics.design2 years ago

I'm looking to model a circuit with a zener diode in it and the exact part doesn't seem to have a simulation model. Looking at the 11 choices in...

I'm looking to model a circuit with a zener diode in it and the exact part doesn't seem to have a simulation model. Looking at the 11 choices in LTspice I see a variety of parameters. The one that I'd probably want to match the most closely is the source resistance, Rs. This seems to be a very difficult number to pin down. The part in question is CZRU52C6V2 by Comchip. They l


minimum 555 duty cycle

Started by panfilero in sci.electronics.design10 years ago 3 replies

does anyone know what the smallest duty cycle is that you can get out of a 555 astable multivibrator? I see the equations for getting under 50%...

does anyone know what the smallest duty cycle is that you can get out of a 555 astable multivibrator? I see the equations for getting under 50% with a diode in parallel with a resistor, but I'm not sure what the minimum pulse width is http://www.kpsec.freeuk.com/555timer.htm much thanks


Kids and Electronics

Started by dcas...@krl.org in sci.electronics.design6 years ago 31 replies

Christmas is coming. So am looking for things that can get the grandkids interested in electronics. My father managed to interest me by making...

Christmas is coming. So am looking for things that can get the grandkids interested in electronics. My father managed to interest me by making with me things as motors out of wire and paper clips, crystal sets using galena and trying to make one using a razor blade as a diode. Books and magazines were good for me, but my grandson does not read a lot. Anyone have some projects