How to make a simple oscillator with transistor and Capacitor?

[sr13579]

I provided a circuit which should discharge at a specific time. But this circuit is not working as an oscillator. How should I make circuit which will give me oscillation?

 

[ChrisP58]

I don't know of a way to make an oscillator with a single transistor. But here is an example of a classic two transistor oscillator.

 

[BobW]

The circuit in the first post might work as an oscillator if you replace the transistor with an SCR.

 

[ronsimpson]

unijunction transistor

 

[ronsimpson]

phase shift oscillator
**broken link removed**

 

[carbonzit]

I don't know of a way to make an oscillator with a single transistor.

Chris, I'm surprised at you. Here's the classic twin-T design, using a single transistor:

(I've built this, it works.)

 

[ChrisP58]

Chris, I'm surprised at you. Here's the classic twin-T design, using a single transistor:
View attachment 114079
(I've built this, it works.)

There's no reason to be surprised. I'm sure that there are lot's of things that you know that I don't. And vice versa.

 

[dknguyen]

There's no reason to be surprised. I'm sure that there are lot's of things that you know that I don't. And vice versa.

Time to cross Chris off my list of omniscient people.

 

[audioguru]

There is an oscillator that uses the reverse-biased emitter-base of a transistor that has avalanche breakdown like a Zener diode (the original schematic in this thread has a Zener diode).
Replace the LED with a speaker to hear it.
Change the value of the capacitor to change the frequency.
It will not work if the battery voltage is too low.

 

[Reloadron]

Give this a read as it will explain in some detail Ron's post.

unijunction transistor
View attachment 114078

You may also want to do a Google of "tunnel diode oscillator circuit".

Ron

 

[Nigel Goodwin]

G

You may also want to do a Google of "tunnel diode oscillator circuit".

Getting a bit esoteric now aren't we?

It also seems fairly obvious that he's looking at audio oscillators, as far as I can recall (never having even seen one) tunnel diode oscillators were for microwave frequencies.

 

[Reloadron]

Getting a bit esoteric now aren't we?

It also seems fairly obvious that he's looking at audio oscillators, as far as I can recall (never having even seen one) tunnel diode oscillators were for microwave frequencies.

Actually Nigel the first tunnel diode oscillator I built was as a kid and maybe the early 60s. It actually ran in the 6 meter ham band or about 50 MHz. I do however agree I was on the esoteric side. OK, we will let it go with a unijunction relaxation oscillator.

Ron

 

[AnalogKid]

There is an oscillator that uses the reverse-biased emitter-base of a transistor

Love that circuit.

ak

 

[AnalogKid]

I don't know of a way to make an oscillator with a single transistor.

Blocking, Clapp, Colpitts, Hartley, Pierce, Vackar, Wein ...

ak