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A forum for the discussion of matters of a technical nature. All such activities are undertaken at the readers discretion and own risk. If you don't know what you are doing, don't blame us if it all goes wrong!
ch25 wrote: ↑11 Jun 2018, 14:02
Not at all. You can use 40MHz crystal to be more sure
Quick question Chris . Any idea why the 2312/2166 have an extra junction between emitter and collector ?
IMG_1627.JPG
Sammy
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30TM060 Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
ch25 wrote: ↑30 Dec 2019, 20:30
Because it have a protection diode inside. Exactly like on your image.
Yeah , but to protect it against what exactly .
30TM060 Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
ch25 wrote: ↑31 Dec 2019, 11:15
Sorry Against inductive load.
OK . Thanks . Technical term would be a flyback diode then Chris ? Cheers , and happy New Year !
30TM060 Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
Got that from our old friend Google . I'd never heard of it myself . Or maybe I did back in 83 when I was in college ....
Cheers
30TM060 Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
So this "flyback" protection diode. Will it potentially blow saving the transistor just that once? Transistor carries on being useful but no more protection the next time?
However you have no way to tell if you have a transistor with 1 or both lives left intact?
Or is it just protection and when that protection is used/gone then the Transistor is gone?
I'm not sure , but I'm assuming that it now physically looks like something like this ... ? (Excuse the crappy Paint editing ..)
Capture_1.JPG
If it does , and the diode junction went open , then I presume it wouldn't make any difference . Is the 2SC1969 the same ? I'm assuming that it's only added in power RF transistors ?
Sammy
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30TM060 Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
Diode does not act like fuse. It just shorts unwanted signal.
Many other transistors have built in diode. Especially those for inductive switching circuits.
WE ARE MOTÖRHEAD, AND WE PLAY ROCK N' ROLL
You can't have too many antennas...
The fakes that are coming in from China are probably cheep low power audio transistors, that's why they don't work well at 27MHz.
The Youtube video linked to in the first post will not differentiate between a genuine RF transistor and a audio transistor.
Crackle wrote: ↑30 Jun 2020, 06:54
The fakes that are coming in from China are probably cheep low power audio transistors, that's why they don't work well at 27MHz.
The Youtube video linked to in the first post will not differentiate between a genuine RF transistor and a audio transistor.
Mike
This is true. But it's entirety down to the individual to do their research prior to buying any transistors including the 1969. If they price is cheap they're most likely cheap copies. Genuine 2sc1969's sell at a premium price these days. The Eleflow CB-20 is a good alternative replacement.
Never, ever, ever....bloody anything ever!
Far too many radio's to list here. But I do own a legal one...