substitute for a manual push button switch

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
Hi guys and Gals, i am new to electronics (about a month and a half) and have a MILLION questions....., however i am only posting my first problem today !

i have built an inductor based voltage booster with a primary coil of an old transformer, 2 capacitors and a switch (and it works, it actually takes the voltage up very nicely when the button is pushed !!)

So having been so infinitely successful with this major achievement (hihihihihi) here is my problem..............

1) as soon as the voltage appears it disappears ........................(want to be able to preset the voltage and once achieved, keep it there and stable)
2) i am using a push button switch. (to "up" the voltage).............(want the circuit to do the switching, i heard about the 555 and a mosfet)
3) even with high voltage (around 50), it wont turn a relatively small motor....(circuit must produce enough amps or miliamps to run the motor at full load)
4) system must be adjustable, varying from 12vdc (with its given miliamp) to around 20vdc (with its given miliamp) (or alternatively adjustable in a 10 - 15volt range either up or down, with a max input volt of 24vdc)

To put you all in the loop !!, i have a small solar panel (20vdc around 11 watt) and want to use this to power a small electric motor !, currently the battery (12vdc) powers it perfectly, but the solar panel(20v) just doesn't have the juice (even though the voltage is higher)..................

as simple as it can be (regards to explanation and schematics) i would appreciate any help !

much appreciated
 

#12

Joined Nov 30, 2010
18,167
Two problems.
1) Boost converters work at frequencies above 20 KHz. They use transistors because your fingers aren't fast enough.
2) There is no circuit which will take, "not enough power" from the solar panel and turn it into, "enough power" to run a motor.
Conclusion? You can't design a circuit that will fix your lack of enough power.
 

#12

Joined Nov 30, 2010
18,167
so i take it i must then get hold of a bigger solar panel ?
Try less solar panel by covering up half the solar panel you have and see if that improves the situation. If it doesn't, you're probably going the wrong direction with this and should try more solar panel.
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
i dont understand !, if the solar gives 20vdc, and i cover half of it, it will only give 10vdc !, as it is the motor wont run on 20vdc how then would it be possible for it to run at 10vdc ?
 

mcasale

Joined Jul 18, 2011
210
Power from the solar panel = (Motor Power)/Efficiency.

The gozinta is always greater than the gozouta.

Are your capacitors in the solar side or the motor side?
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
To put you all in the loop !!, i have a small solar panel (20vdc around 11 watt) and want to use this to power a small electric motor !, currently the battery (12vdc) powers it perfectly, but the solar panel(20v) just doesn't have the juice (even though the voltage is higher)..................

is there a circuit i can build that will "juice up" the output of the solar panel enough to power the motor ? (mabey an inductor, coupled with a mosfet amd a 555 playing the role of the manual switch)
 

GopherT

Joined Nov 23, 2012
8,012
To put you all in the loop !!, i have a small solar panel (20vdc around 11 watt) and want to use this to power a small electric motor !, currently the battery (12vdc) powers it perfectly, but the solar panel(20v) just doesn't have the juice (even though the voltage is higher)..................

is there a circuit i can build that will "juice up" the output of the solar panel enough to power the motor ? (mabey an inductor, coupled with a mosfet amd a 555 playing the role of the manual switch)
The voltage of a solar panel is not the issue. The amount of current that the panel can push is what is key. So, at 20V and 11W, that is about 0.5 amps. If your motor needs more than o.5 amps, (500 mA), then you need a different option.
 

GopherT

Joined Nov 23, 2012
8,012
do you have an option ?.......... is there any way i can boost the current ?
1) Additional solar panels

2) Use the solar panel to charge a 12V battery and run the motor off of the battery

3) Use a smaller motor (less current draw). A gear motor might be an option to give you a slow, high torque motor.
 

Thread Starter

Knowlittle

Joined Mar 16, 2016
45
Excellent ideas Gopher ! Thanks

All i need now is a small (SIMPLE) sceamatic for a battery charger that runs off my solar panel !, could you provide ?

thanks
 

electrophile

Joined Aug 30, 2013
126
@GopherT is right! What you need pay attention to is the total power output of the panel (11W in your case). If the motor has a power rating that can be driven with this power then you are good to go (assuming 100% efficiency which is unreal in the real world). Look at using an integrated chip that monitors and charges your battery while the battery drives the motor. Perhaps something like this: http://www.linear.com/solutions/1465.
 
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