BC547B(npn) & BC557B(pnp) comes to my mind.I tend to use BC327/337, as those have higher Ic (800mA versus 100mA), being more useful for switching loads like relays or common anode/cathode of MUX-ed displays.
Be warned that the BC series uses the CBE instead of more common ECB pinout.This is not always true.
The BC547 & BC557 have a higher current gain than the BC327 & BC227. I like to get the BC547C and BC557C because they have a high beta and aren't much more expensive than the B variants.BC547B(npn) & BC557B(pnp) comes to my mind.I tend to use BC327/337, as those have higher Ic (800mA versus 100mA), being more useful for switching loads like relays or common anode/cathode of MUX-ed displays.
BC547/557 is interesting as the A type have the least gain, while the C type the most. I settled in B-type in my own choice (as now), because the pricing, but let see what is the final decision.The BC547 & BC557 have a higher current gain than the BC327 & BC227. I like to get the BC547C and BC557C because they have a high beta and aren't much more expensive than the B variants.BC547B(npn) & BC557B(pnp) comes to my mind.I tend to use BC327/337, as those have higher Ic (800mA versus 100mA), being more useful for switching loads like relays or common anode/cathode of MUX-ed displays.
BC547B(npn) & BC557B(pnp) comes to my mind.
I tend to use BC327/337, as those have higher Ic (800mA versus 100mA), being more useful for switching loads like relays or common anode/cathode of MUX-ed displays.
The BC547 & BC557 have a higher current gain than the BC327 & BC227. I like to get the BC547C and BC557C because they have a high beta and aren't much more expensive than the B variants.
Use the BC547 & BC557 for linear amplifiers. They have a higher bandwidth than the BC327 & BC337 and I believe are lower noise too.
ProElectron CodingSo the European system actually have some information coded in, compared to JEDEC 2Nxxxx codes.
An Introduction.
Once upon a time, long ago, British and European transistors were commonly coded as valves: 0 = no heater, C = triode. However it was quickly realised that everything would end up as an OC something or other (likewise with diodes, which would all become OAxx) and could be confused with existing cold-cathode valve types. So the ProElectron organisation developed a new system of coding semiconductor devices and the one in use today. Basically, British and European transistors are issued with a unique combination of letters and numbers.
The first letter identifies the semiconductor type:
· A = Germanium
· B = Silicon
· C = Gallium Arsenide
· D = other compound semiconductor material
The second letter indicates the intended use:
· A = Small signal diode
· B = Varicap diode
· C = Small signal LF transistor
· D = LF power transistor
· E = Tunnel (Ersaki) diode
· F = RF small signal transistor
· K = Hall effect device
· L = RF power device
· N = Optocoupler
· P = Radiation sensitive device (e.g photo transistor)
· Q = Radiation emitting device (e.g LED)
· R = Low power SCR
· T = High power SCR or triac
· U = High voltage switching transistor
· Y = Rectifier diode
· Z = Zener diode
the 150 volt 2N5401 and 2N5551 would be more suitable.
I agree with T3sl4co1l's commendation for the MPSH10/MPSH81 and MMBTH10/MMBTH81 as faster TO-92 and surface mount parts. Just do not expect RF transistors to perform well as fast saturated switches in switching applications.
Get a small signal schottky diode like the 1N5711, BAT41, or BAT83 for use in baker clamps if you want to improve switching. The BAT41 with its 100mA current rating can do double duty in low current switching regulators.
There are too many MOSFET options for me to make a good recommendation. The problem with many of them is marginal switching on 3.3 or even 5 volts; the true logic level ones are more expensive.
The BC547 & BC557 have a higher current gain than the BC327 & BC227. I like to get the BC547C and BC557C because they have a high beta and aren't much more expensive than the B variants.I also stock the C series for the same reason, and the 'low noise, higher voltage' 550/560s since there is no great price difference.
But there is a catch, that I first heard of from Bob Pease: the higher the beta, the lower the output impedance. It can be seen in this datasheet (http://pdf.datasheetcatalog.com/datasheet/vishay/85113.pdf): the 547A has 55.5k typical output impedance, the 547B 33.3k, and the 547C 16.6k, and it could go as low as 9k!. This can be very important when building current sources/sinks, active loads, etc.
the 150 volt 2N5401 and 2N5551 would be more suitable.
Or the similar MPSA46, or whatever they are, from that family. MJE350 and complement are also quite popular for audio (driver stage), though the datasheet is sorely wanting. I think On Semi makes a detailed datasheet? Or, there are equivalent parts with good data out there, shop around.
The BD135 through BD140 are like that also. The ST and Fairchild datasheets say nothing about dynamic performance but there are SavantIC Semiconductor (who?) datasheets which say 190 MHz for the NPNs and 160 MHz for the PNPs. What?
Sorry for going a bit off topic, but honestly, I'm confused beacuse this beta thing has been bothering me for a time. Do you mean that there is a workaround for low rout, or that it's not relevant for current sinks and active loads? I've gone back to basics to see if I got this wrong, redoing example 2 here: http://leachlegacy.ece.gatech.edu/ece3050/notes/ISources/isources.pdf (http://leachlegacy.ece.gatech.edu/ece3050/notes/ISources/isources.pdf) [There is an errata in the exercise: they changed m for n]. I attach the python code I used:But there is a catch, that I first heard of from Bob Pease: the higher the beta, the lower the output impedance. It can be seen in this datasheet (http://pdf.datasheetcatalog.com/datasheet/vishay/85113.pdf): the 547A has 55.5k typical output impedance, the 547B 33.3k, and the 547C 16.6k, and it could go as low as 9k!. This can be very important when building current sources/sinks, active loads, etc.
Only relevant to pure current mirrors without degeneration.
Tim
beta = 100.0 # Current gain.
Va = 75.0 # Early voltage.
Vbe = 0.65 # Base-emitter voltage.
Vce = 8.00 # Collector-emitter voltage.
rx = 40.0 # Base spreading resistance.
Ic = 1.5e-3 # Collector current.
Vcc = 15.0 # High rail.
Vdd = -15.0 # Low rail.
n = 2.0 # Emitter resistor Vbe multiplier.
m = 10.0 # Stiff current multiplier at the base.
Vt = 300.0*1.3806e-23/1.6022e-19 # Thermal voltage.
alpha = beta/(1+beta)
Re = (beta*n*Vbe)/((1+beta)*Ic)
R1 = beta*(Vcc-Vdd-(n+1)*Vbe)/((m+1)*Ic)
R2 = (beta*(n+1)*Vbe)/(m*Ic)
r0 = (Va + Vce)/Ic
rep = (R1*R2/(R1+R2) + rx)/(1+beta) + alpha*Vt/Ic
rout = (r0 + rep*Re/(rep+Re))/(1.0 - (alpha*Re)/((rep+Re)))
print "beta ", beta
print "va ", Va
print "Vt ", Vt
print "Re ", Re
print "R1 ", R1
print "R2 ", R2
print "r0 ", r0
print "rep ", rep
print "Output resistance: ", rout
If the seller do refuge to sell outside the US. why you would suggest he would change his mind if someone in Europe would asks. Will no happen, especially since the products are in "high-tech" category, which have had traditionally paranoid export limits / licencing.The 4117 were my list just because it is what it is and it still is available in the discrete form. Unfortunately the A-subtype is not hobbyist friendly priced in any form, while MMBF4117 is. (unfortunately in SMD, but luckily SOT23 is still somewhat usable, without PCB and professional equipment.) :)
There is a US seller who has PN4117As at a decent price:
http://www.ebay.com/itm/QTY-100-PN4117A-N-Ch-JFET-General-Purpose-Amplifier-/371603063222 (http://www.ebay.com/itm/QTY-100-PN4117A-N-Ch-JFET-General-Purpose-Amplifier-/371603063222)
Maybe he would ship you some, if you ask nicely.
Indeed. China to Europe is cheaper than US to Europe!
... and PN/MMBF4393 in most packages are easy to find and inexpensive. ...Obsolete, according to Farnell :(
... and PN/MMBF4393 in most packages are easy to find and inexpensive. ...Obsolete, according to Farnell :(
Sorry for going a bit off topic, but honestly, I'm confused beacuse this beta thing has been bothering me for a time. Do you mean that there is a workaround for low rout, or that it's not relevant for current sinks and active loads?
Edit: Aha, I found it! What was spoiling the resistance of the current source was not the Va, but the choice of resistors R1 and R2. For high beta you need a much stiffer current at the base divider, m=100 or so. I think I'll need to think this over, much deeper. :-+ Thanks!
How disturbing it is that VHF means very high frequenzy in a 30 MHz to 300 MHz range while every dog collar today transmit in Gigahertz range Wifi. Anyone else annoyed. >:D ^-^The designations LF, MF, HF, VHF, UHF etc. came about when electronics were much slower, than they are today.
Yep, when the silicon were still used for rectifier casings and not rectifying material. ::)How disturbing it is that VHF means very high frequenzy in a 30 MHz to 300 MHz range while every dog collar today transmit in Gigahertz range Wifi. Anyone else annoyed. >:D ^-^The designations LF, MF, HF, VHF, UHF etc. came about when electronics were much slower, than they are today.
Anyone seen sot-23 to to-39 canning machine cheaply on chinese evilbays??? :D
But back in the day they used to handpick the 3-transistors used to every lunar lander and much details were given to select the right biasing currents for certain tolerance lot of transistors. :D ...But I can bet that at least half of the writers on this topic do have hands-on experience on this particular thing and not just "I have read about this historic procedure" like me.
I found TIP30's in my junkbox date code 1973. hFE measured 5. Tossed them in the garbage.
40+ years later, TIP30 still available and same specs. fT 3MHz, hFE 15-40, 30W.
Old parts don't have a lot of tests and datasheet specs so they are easy to rip off.
What's worse, nobody tests this. And even worse, manufacturers keep adjusting their processes... And on top of this a lot of rumors (esp. about audio stuff where audiophiles "reason" about sound quality with no understanding of how opamps work and no measurements).
Is there a general rule of thumb for high(ish) voltage (ie. 100V to 140V range), but low leakage (Vce and maybe Vbe) BJT transistor type. ...Or is the higher voltage the rule of thumb to find lower leakage type.
** Low leakage, <15nA **
**When searching that transistor model***
PS. If we still try to stay on "general purpose" category.
If it meets the datasheet, and your application works based on datasheet information, then you're fine.
Makes sense, thx. PS. I just noticed that at least some types of PN2222 are "rated" to 10nA Icbo max. at 25 deg.C. I'm more and more confident the bulk box of cheap as dirt (they are sand after all) parts (from reputable source) is right way to go forIs there a general rule of thumb for high(ish) voltage (ie. 100V to 140V range), but low leakage (Vce and maybe Vbe) BJT transistor type. ...Or is the higher voltage the rule of thumb to find lower leakage type.
** Low leakage, <15nA **
**When searching that transistor model***
PS. If we still try to stay on "general purpose" category.
Leakage depends more on area, construction, processing, and temperature than voltage rating. For small signal transistors, it is only tested down to a level of 10s of nanoamps because that covers almost all applications and a more sensitive test would take longer.
Voltage rating has more of an effect on recovery time.
A thorough search will turn up transistors tested down to 10 nanoamps but I think of low leakage as 10 picoamps and lower which I have had no trouble finding in common parts like the 2N3904.
It would be interesting to know if the garden variety actually do have different internals between models or are they actually just from one outcome from a machine and then sorted to meet different key specifications of garden variety part numbers. I wouldn't be too surprised (without having even general knowledge of semiconductor production) if this would be the case looking at how close the specks are in many parts.
If it's not on the datasheet, you have to test it yourself. Fine for breadboarding, or small run test equipment, say. Not so great for production.
Wouldn't life be easier if, instead of the JEDEC/whatever part numbering scheme evolving, we'd had something like the National book. Here's the set of dies, here's the parameters we actually test and here's the bins we put them into and the part numbers for those bins.
I still find myself going to the (defunct) National databook to find a suitable part from time to time just because the layout by process makes it easier to navigate.
the 150 volt 2N5401 and 2N5551 would be more suitable.
Or the similar MPSA46, or whatever they are, from that family. MJE350 and complement are also quite popular for audio (driver stage), though the datasheet is sorely wanting. I think On Semi makes a detailed datasheet? Or, there are equivalent parts with good data out there, shop around.
Did you mean the MPSA43/MPSA93? They are a little slower.
The Motorola/On MJE371/MJE521 are the same way. They are recommended for specific applications but lack a full set of specifications. I ran across them when doing a search for fast TO-126, TO-225, and TO-220 parts to use in high performance regulators.
The BD135 through BD140 are like that also. The ST and Fairchild datasheets say nothing about dynamic performance but there are SavantIC Semiconductor (who?) datasheets which say 190 MHz for the NPNs and 160 MHz for the PNPs. What?
How disturbing it is that VHF means very high frequenzy in a 30 MHz to 300 MHz range while every dog collar today transmit in Gigahertz range Wifi. Anyone else annoyed. >:D ^-^
Band name | Abbreviation | ITU band number | Frequency | Wavelength | |
Extremely low frequency | ELF | 1 | 3–30 Hz | 100,000–10,000 km | |
Super low frequency | SLF | 2 | 30–300 Hz | 10,000–1,000 km | |
Ultra low frequency | ULF | 3 | 300–3,000 Hz | 1,000–100 km | |
Very low frequency | VLF | 4 | 3–30 kHz | 100–10 km | |
Low frequency | LF | 5 | 30–300 kHz | 10–1 km | |
Medium frequency | MF | 6 | 300–3,000 kHz | 1,000–100 m | |
High frequency | HF | 7 | 3–30 MHz | 100–10 m | |
Very high frequency | VHF | 8 | 30–300 MHz | 10–1 m | |
Ultra high frequency | UHF | 9 | 300–3,000 MHz | 1–0.1 m | |
Super high frequency | SHF | 10 | 3–30 GHz | 100–10 mm | |
Extremely high frequency | EHF | 11 | 30–300 GHz | 10–1 mm | |
Tremendously high frequency | THF | 12 | 300–3,000 GHz | 1–0.1 mm | |
Ridiculously high frequency | RHF | 3–30 THz | 100–10 μm | ||
Fantastically high frequency F***ing high frequency | FHF | 30–300 THz | 10–1 μm | ||
Obscenely high frequency ** Optically high frequency | OHF | 300–3,000 THz | 1–0.1 μm | ||
Preposterously high frequency | PHF | 3–30 PHz | 100–10 nm |
I have started to think that I stock a few hundredHi Vtile
general purpose through hole transistors (an investment of a few tens of bucks). To be sure I will have them to tinker around as to me it seems that the jellybean variety is vanishing or vanished already from THTs.
I'm mostly thinking of small signal, low freq (<200MHz), throw in buffer etc. general purpose uses of tinkering and maybe slobby repair or hack here and there.
BJTs:
BC547B(npn) & BC557B(pnp) comes to my mind.
Is there other worth to look that are still readily available.
Darlington models to maybe look at?
.
JFET
Is there cheapish (<$0.50 ) replacement for 2n4117 other than mbf4117(smd). It seems to be pretty alone in fart detector range.
MOSFET
For logic level switching use. Any ideas, in leds/signals on/off range of power. Should be also as robust as possible for ESD and ideally should have the protective diodes. 2N7000 ?? or were it JFET&BJT hybrid, hmm.
Known matched pairs (for that random differential stage) that wouldn't cost arms and legs and could still be found as THTs. ..none or should I look from IC listings..
Any other than TO-92 cases to look at for jellybean THT parts. Metal cans seems to be premium only now.