Electronics-Related.com

Not OT: BC850 as a diode clamp?

Started by Ricky in sci.electronics.design2 years ago 53 replies

A differential input amp is using BC850 transistors with the base tied to the collector as a clamp to ground. What is better about this than a...

A differential input amp is using BC850 transistors with the base tied to the collector as a clamp to ground. What is better about this than a diode? I guess it can handle a lot more current before the voltage starts to rise? https://html.scribdassets.com/9r5y0a5pxc35p3zy/images/4-1adb6b3466.jpg -- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts...


1N34A Germanium Diode finally found!!

Started by Anonymous in sci.electronics.design11 years ago 49 replies

I finally found some 1n34a diodes and one of my new favorite sites! http://www.bgmicro.com/1n34a-germanium-diode.aspx

I finally found some 1n34a diodes and one of my new favorite sites! http://www.bgmicro.com/1n34a-germanium-diode.aspx


guard rings

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

Some schottky diodes have a PN junction in parallel, a "guard ring" that acts like a parallel zener to improve ESD specs, and may help with the...

Some schottky diodes have a PN junction in parallel, a "guard ring" that acts like a parallel zener to improve ESD specs, and may help with the fab somehow. That's OK, but at high currents the PN diode can turn on, and it's slow to turn off and can even act like a step-recovery diode. I wonder if there is a way to tell, from the data sheets, if there is a guard ring. VI curve? CV curve? ES...


Schottky diodes for RF application

Started by amal banerjee in sci.electronics.design5 years ago 3 replies

Could someone here shed some light on this ? I am experimenting with envelope detection at RF frequencies with SPICE. The mixer is a simple...

Could someone here shed some light on this ? I am experimenting with envelope detection at RF frequencies with SPICE. The mixer is a simple SPICE B signal source as B0 3 4 V(1)*V(2) where 1, 2 are the nodes at which the two signal sources are attached. THe mixer output is fed into a Schottky diode(1N5818, BAR42 etc.,) and a shunt capacitor is attached to the Schottky diode cathode. ...


Bipolar transistor bias question

Started by billbowden in sci.electronics.design8 years ago 62 replies

I have a switching application where a single bipolar transistor might be used. The AC input is about 300mV and the transistor needs about 700...

I have a switching application where a single bipolar transistor might be used. The AC input is about 300mV and the transistor needs about 700 mV to switch on. My idea is to construct a voltage divider using a diode which will produce about a 600mV drop across the diode and a voltage divider of 2 equal resistors to set the transistor base voltage at about 300 mV so the transistor will sw...


LT Spice diode C-V graph

Started by John Larkin in sci.electronics.design10 years ago 55 replies

What's an easy way to plot the C-V curve of a back-biased diode? Maybe a constant-current ramp, then a differentiator, and a little math...

What's an easy way to plot the C-V curve of a back-biased diode? Maybe a constant-current ramp, then a differentiator, and a little math block? Or, flip that over, constant voltage ramp and current sensor, less math. Low level AC voltage on top of a DC sweep, and some sort of AC current detector? (Fake Boonton) -- John Larkin Highland Technology, Inc jlarkin a...


faston connector spacing

Started by Winfield Hill in sci.electronics.design5 years ago 2 replies

Our RIS-796 250-amp LED current pulser has been operated up to 1100A by Rob Legg, and is well suited to make shaped current pulses up to...

Our RIS-796 250-amp LED current pulser has been operated up to 1100A by Rob Legg, and is well suited to make shaped current pulses up to 750 amps. E.g., "8.3ms single half sine-wave" for "Peak forward surge current" diode testing. Manufacturers like to make rating plots for 1 to 100 cycles, etc. For example, a SMD or SMC diode I'm considering is rated at 350A for one cycle, dr...


Power supply for Buck dc-dc

Started by Anonymous in sci.electronics.design12 years ago 19 replies

Hi, Please, could I use a half-bridge diode circuit to power this buck power supply...

Hi, Please, could I use a half-bridge diode circuit to power this buck power supply ? http://www.ebay.com/itm/ZXY6005-DC-DC-60V-voltage-and-current-constant-power-supply-module-/1906 49685203?pt=LH_DefaultDomain_0&hash=item2c639b54d3 This power supply accepts 62VDC input, so if I use one rectifier diode to rectify 120Vac home's power (decay to ~ 54Vdc), it will work ? 120Vac -> 1 rectif


USB to TP4056 charger - why is the diode there?

Started by Peabody in sci.electronics.design4 years ago 4 replies

This is the relevant part of the schematic of an 18650 battery charger and boost converter (to 5V)...

This is the relevant part of the schematic of an 18650 battery charger and boost converter (to 5V) module: https://i.postimg.cc/Tw7X35Fq/USB-to-TP4056.jpg And here's the module: https://www.aliexpress.com/item/32870411748.html Coming from the USB power pin, there's a series Schottky diode and a very low value resistor. The resistor is found in the TP4056 datasheet typical applic...


What diode to use for a primary side rcd clamp?

Started by Johann Klammer in sci.electronics.design2 years ago 3 replies

Specifically the LNK616 flyback regulator. They have 1N4007 in their dataheets/appnotes. But the 1N4007s trrs are all over the place. Often...

Specifically the LNK616 flyback regulator. They have 1N4007 in their dataheets/appnotes. But the 1N4007s trrs are all over the place. Often around 1us. The regulator has a minimum on-time of 700ns, and really does not like surge currents. What are better specced alternatives?


Unconnected part LTSpice seems to need (weird ...)

Started by Joerg in sci.electronics.design13 years ago 81 replies

Folks, This is close to voodoo but repeatable. Unfortunately I can't disclose the schematic since it is for a client. Just wondering , anyone...

Folks, This is close to voodoo but repeatable. Unfortunately I can't disclose the schematic since it is for a client. Just wondering , anyone had this before? At the far end of a TX line I used to have a diode connected across because a previous version of a chip would have such a substrat path. Nice waveforms, fast sims. Everything as expected and peachy. Now the new iteration of the c...


cute little switcher

Started by John Larkin in sci.electronics.design1 year ago 4 replies

https://www.dropbox.com/scl/fo/cx2tgk4xexj134kck54js/h?rlkey=qrp95nd26g5zy2bjqce1k5pfa&dl=0 Diodes Inc AP63300. This will switch +48 down to...

https://www.dropbox.com/scl/fo/cx2tgk4xexj134kck54js/h?rlkey=qrp95nd26g5zy2bjqce1k5pfa&dl=0 Diodes Inc AP63300. This will switch +48 down to 5/12/24 or whatever. I tested it because sometimes synchronous switchers make horrendous noise spikes, but this looks pretty good. The trick seems to be to tweak the doping so the substrate diode isn't an SRD.


HV indicator

Started by Eddy Lee in sci.electronics.design1 year ago 23 replies

I often have to measure the difference of two 392V sources. Unfortunately, sometimes it become the sum, using a one-time fused muti-meter. I...

I often have to measure the difference of two 392V sources. Unfortunately, sometimes it become the sum, using a one-time fused muti-meter. I am thinking about using a rectifier diode (for direction) , 6V zener (for voltage), 6V 5W light bulb (for current) and 10 ohms resistor. Will it work? Perhaps 22 or 33 ohms resistor?


Simple pulse stretcher

Started by George Herold in sci.electronics.design12 years ago 94 replies

Hi guys, I need a little digital pulse stretcher. I've got pulses that are 5ns to 25ns in width, and I'd like to bump them all up to all be at...

Hi guys, I need a little digital pulse stretcher. I've got pulses that are 5ns to 25ns in width, and I'd like to bump them all up to all be at least 10ns. I've got a few spare 74HC14 inverters. I was thinking of just feeding one through a diode followed by an R/C to ground. Any other ways? There might be an extra AND gate too. (not my circuit so I'm not quite sure.) Thanks George...


Negative resistance with BJTs

Started by Anonymous in sci.electronics.design6 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.


TVS diode in LT spice

Started by John Larkin in sci.electronics.design2 years ago 4 replies

.model SMCJ33A D(Ron=.4 Roff=8Meg Vfwd=.7 epsilon=100m Vrev=38.65 Vpk=33 revepsilon=4 mfg=Littlefuse type=TVS) That's in the standard library....

.model SMCJ33A D(Ron=.4 Roff=8Meg Vfwd=.7 epsilon=100m Vrev=38.65 Vpk=33 revepsilon=4 mfg=Littlefuse type=TVS) That's in the standard library. It behaves like a symmetric zener. Why? Does "type" do that? There are unipolar TVS diodes, too.


temperature compensating a laser diode

Started by John Larkin in sci.electronics.design12 months ago 5 replies

LEDs and lasers get way more efficient when they are cold. But their junction drop increases too. So it seems that driving them from...

LEDs and lasers get way more efficient when they are cold. But their junction drop increases too. So it seems that driving them from some magical Thevenin source would temperature compensate the light output. Has anyone done this? I need to hold some dBm level from a laser source from -40 to +85C and that might be a simple way to do it.


Turbo Royer/Baxandall in boost configuration

Started by bitrex in sci.electronics.design3 years ago 62 replies

Is it possible to take your standard Baxandall and tap the capacitor, take an aux winding off the secondary and feed a somewhat higher DC...

Is it possible to take your standard Baxandall and tap the capacitor, take an aux winding off the secondary and feed a somewhat higher DC voltage to the cap (through the usual two-diode supply handoff arrangement), and use it to feed the gate drive to the transistors as well, which would be clocked rather than self-oscillating. The goal would be to have a quiet step-up converter that co...


rf distance measurement

Started by chris in sci.electronics.design2 years ago

> Anyone know of any ICs designed for measureing distances with RF? I'm thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one...

> Anyone know of any ICs designed for measureing distances with RF? I'm thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one foot. The basic method of one device emitting a signal and another echoeing it back would be attractive. > Any recommendations? > > Hul Dunno about ic's, but I would look at 10 GHz gunn diode intruder alarm modules as a starting point.


speaking of substrate diodes...

Started by Anonymous in sci.electronics.design3 years ago 2 replies

leads to this one... https://www.dropbox.com/s/cgaxalnn3hhf315/RRIO_Logamp.jpg?raw=1 where we use the substrate diode of a RRIO opamp as a...

leads to this one... https://www.dropbox.com/s/cgaxalnn3hhf315/RRIO_Logamp.jpg?raw=1 where we use the substrate diode of a RRIO opamp as a logarithmic current-to-voltage converter. There are better ways to do this, but maybe none so cute. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable whe...