Amplifying current of an oscillator circuit

AnalogKid

Joined Aug 1, 2013
10,177
I suspected that. If so, then that is not the aspect of real life components that I an referring to. Variations in Vbe have a direct impact on power sharing among paralleled transistors. This is why large power amplifiers have ballast resistors in the emitters of paralleled devices.

One transistor has a slightly smaller Vbe, so it has a slightly higher base current, and collector current, and power dissipation. The higher power dissipation causes more heating (relative to the other device), which decreases its Vbe even more (relative to the other device), which increases its base current, collector current, and power dissipation even more. and on and on.

ak
 

Danko

Joined Nov 22, 2017
1,492
If you run the post #39 sim for 5mS you get a decaying oscillation. I don't think that's what the TS is expecting.
@Alec_t
I checked asc from post #39. See result below.
Anyway, thanks for concern about TS's expectation.
1628878037978.png
I suspected that. If so, then that is not the aspect of real life components that I an referring to. Variations in Vbe have a direct impact on power sharing among paralleled transistors. This is why large power amplifiers have ballast resistors in the emitters of paralleled devices.

One transistor has a slightly smaller Vbe, so it has a slightly higher base current, and collector current, and power dissipation. The higher power dissipation causes more heating (relative to the other device), which decreases its Vbe even more (relative to the other device), which increases its base current, collector current, and power dissipation even more. and on and on.
@AnalogKid
You are right. I am working on it.
 

Danko

Joined Nov 22, 2017
1,492
Now I want to amplify its current upto 100mA amplifying the overall power of the signal
I actually want to design an AM modulator(Switching modulator) and this oscillator produces the carrier wave.I am planning to use a 1N4148 diode as a switching device,for proper modulation the diode needs to be in linear region that means high current that is why I need about 100mA of current
@DD Ki Vines, try circuit below.
Power, dissipates by Q1, is 58mW.
1629235214993.png
 

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