Automatic On Off Switch

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
Hallo out there all my learned out there ! I am in need. ... i have constructed a circuit with a coil a few caps and a manual switch. When pressing the switch the voltage would climb. I need 2 things ...1) need to "override" the manual switch with an automated one so the circuit switches automatically 2) stabilize the output voltage ! I hope you can assist !!
 

Alec_t

Joined Sep 17, 2013
10,716
Without a schematic (or at least a block diagram) of your circuit and a better description of it's intended function it will be difficult to assist.
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
I understand. When the coil and the battery is connected and the button is pushed repeatedly it "pumps up" the voltage (quite a bit), what i want to do is replace the manual switch with an automated one (dowing the pressing on my behalf), then before the output i want to "bank" the captured voltage. Almost like a stun gun. No real purpose for the circuit yet, but sure when it works i will find a purpose for it.
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
Thank you very much, appreciated! ! Can you mabey suggest a sceamatic i can try to maintain this voltage ?, even small voltage is good around 12v with sufficient current ?
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
Thanks alot, I do understand what you are saying, and really appreciate your assistance ! im trying ! (Hihi) ! Thanks again.
 

dl324

Joined Mar 30, 2015
9,589
Thanks alot, I do understand what you are saying
There's not really much point in driving the switch with a fixed frequency, fixed pulse width oscillator. You need a feedback loop to control the output voltage.

Don't try it without voltage regulation; you'll just damage your caps and/or transistor.
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
Guys please bear with me, ive been doing this for only a month now ! I really am not stubborn or arrogant !!, im just having a hard time understanding some of the things (i always try to apply logic) ! Ok what i am trying to build is a small very simple variable dc powered transformer (power supply), say you would input 3v, but run components to rhe "value" of 5volt.....would this be at all possible ! ..... sorry again if i sounded at all arrogant !! My apologies!
 

Alec_t

Joined Sep 17, 2013
10,716
So, what you're after is a DC/DC converter. There is plenty of literature about those on the net, and a quick google should find you heaps of example circuits.
 

AnalogKid

Joined Aug 1, 2013
8,251
All he wants to do is switch the switch on and off really fast. (POST #6) He thinks he's going to get a higher usable voltage that way. It isn't going to work.
Yes, it is.
I'm done with this post.
Good.

Post #3 and post #6 clearly indicate a diode. As both dl and Alec managed to figure out, but you cannot, is that he is trying to reinvent a regulated boost converter. Without knowing the details, he has recreated one of Faraday's experiments and is asking about a) how to drive the switch continuously so that the boosted output voltage is continuous; and b) how to stabilize the output voltage over a range of load currents. While neither of these is an entry-level or beginner's-level question, both will "work". If you will recall, the Kettering automobile ignition system went on sale in 1910. Also, all CRT displays starting with TV sets in the 1930's have a similar circuit, as do every laptop, cell phone, and tablet battery charger ever made. I'm not sure if the total number of flyback power supplies produced is over 1 trillion, but if not, it's close. So I think this circuit has promise.

ak
 
Last edited:

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
Thank you AnalogKid....You understand exactly 100% what i want to accomplish !

" regulated boost converter. Without knowing the details,........ a) how to drive the switch continuously so that the boosted output voltage is continuous; and b) how to stabilize the output voltage over a range of load currents.............So I think this circuit can work."

Well as i said, i am very new to this (still battling to read basic schematics), but my "Logic" tells me that the idea i have, which AnalogKid so adequately explained, could work !

So ... who can help, or are you going to make me suffer (hihi)

Cheers


"
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
Thank for the link, this however is exactly what i built, my question now is how do i maintain the boosted output voltage and keep it continuous
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
looking at this schematic, it seemt to be what i am looking for in regards to the switching, but will the cap serve as a continous "regulated" output boost converter.gif ?
 

#12

Joined Nov 30, 2010
18,170
No. There is a bunch of smart stuff between the capacitor and the base of the transistor.
I don't know whether to say it's bad or good, but you're a little late to the party on this one.
I'm not sure if the total number of flyback power supplies produced is over 1 trillion, but if not, it's close.
My point is, you can buy a chip to do all the smart stuff for a couple of dollars.
 
Top