that site is bookmarked and this look promising. i have gone with this value according to the detail and what is available on ebay. chose this resistor and this diode. do you have any comment on the gate and where to get non IC?

You are relying way too heavily on the simulation. + Remove the 12V 10W bulb from the sim circuit. Your not going to operate a 10W 12V bulb with a 9V battery. @ 9V to obtain 10W you will need more than 1A of current and the 9V batery can not manage this.

Zener Regulator Calculator

 

that site is bookmarked and this look promising. i have gone with this value according to the detail and what is available on ebay. chose this resistor and this diode. do you have any comment on the gate and where to get non IC?

A 10V zener and the diode are going to get you in trouble:

Now, instead of regulating the voltage at 10.5V you are regulating it at 10.0V, then you are adding a diode before the battery. This leaves you with 10.0V - 0.7V or 9.3V. This is just shy of 1.33V/cell which is far from fully charged.

perhaps you can explain to me what happens when S2 is in either position.
What is the purpose of D1?

 

my thinking for d2 was that it will only allow current to flow one way and not mess up my source and will act as some type of a safety device but i completely forgot to include the power consumption. anyway around this? good thing you are here. as for the s2 switch i think i have explain it in a previous post but maybe is a wrong way to go about it.

-no power from source = run off battery
-s2 connect will power ldr from source
-s2 connect will charge the battery

 

my thinking for d2 was that it will only allow current to flow one way and not mess up my source and will act as some type of a safety device but i completely forgot to include the power consumption. anyway around this? good thing you are here. as for the s2 switch i think i have explain it in a previous post but maybe is a wrong way to go about it.

-no power from source = run off battery
-s2 connect will power ldr from source
-s2 connect will charge the battery

A DPDT switch can eliminate the need for the diode. The 10V Zener is a bit low for fully charging the 9V battery, but will do a bit better with the diode removed. The cell voltage can go as high as 1.43V as apposed to 1.33V. Ideally something near 1.5V/cell is best.

Also: The logic gates involved, The output to the LED circuit is a logic level 5V, I believe and probably miniscule current.
Can you explain what the gates are doing and the function of S1? It appears that you want the 2 LED's circuit on at all times, Yes?

 

not sure what you mean when you say the logic level is at 5V. the gate shows 10V. both of these gate are used to allow current flow only when they achieve the right instruction when the two thing i mention happen to make it simplier and avoid having too many manual switches. i do want the 2led to be always on in low light and s1 give me the option to switch it off. some of this thing will be in its own compartment and is connected with a long wire. 12v and s1a is one(inyour) and is meant to be unplug. i can explain more in detail if you need it but ill also check if it will work without it.

i have a few spst switches laying around so can it replace your s1b and still have it function as a reserve? playing with the simulation and so far the 2led wont go on unless i turn off R2 and the 9v isn't powering my load.

 

not sure what you mean when you say the logic level is at 5V. the gate shows 10V. both of these gate are used to allow current flow only when they achieve the right instruction when the two thing i mention happen to make it simplier and avoid having too many manual switches. i do want the 2led to be always on in low light and s1 give me the option to switch it off. some of this thing will be in its own compartment and is connected with a long wire. 12v and s1a is one(inyour) and is meant to be unplug. i can explain more in detail if you need it but ill also check if it will work without it.

Yes, the I was wrong about the 5V. it will be 10V - 12V.

i have a few spst switches laying around so can it replace your s1b and still have it function as a reserve? playing with the simulation and so far the 2led wont go on unless i turn off R2 and the 9v isn't powering my load.

Two SPST switches will work fine. But the current will not be more than 10mA as per the datasheet of the 4001B series device. This will not power the LED's.



Does this circuit have anything to do with power failures, in other words, if the 12V source is gone it will still run and when the main supply is connected, it will run and charge the battery that was used when the power was out?

 

Two SPST switches will work fine. But the current will not be more than 10mA as per the datasheet of the 4001B series device. This will not power the LED's.

the gate have been changed to suit this new schematic. what would happen if both s3 and s1 connect? will it both send power to my 2led and load at the same time? if so will it destroy the system because it does not have enough juice to charge the battery and at the same time power the load? or will it be supported by the output of the 9V?

i don't think a gate will be an option for me anyway seeing how it isnt adequate enough to send power. what component will be a suitable replacement?

Does this circuit have anything to do with power failures, in other words, if the 12V source is gone it will still run and when the main supply is connected, it will run and charge the battery that was used when the power was out?

yes i need it to perform something like that. 12V being the street power and 9V being the house backup generator.

 

Although I noticed this last night I did not mention it as it was late. The way the LED's are wired now they will never turn on. I was too busy concentrating on getting a decent charging circuit that I was not concerned with the LED's at the time.

Here's how your LED's need to be hooked up. Biasing the base of the transistor
allows the full path for current to flow from 12V/9V thru the resistors...LED's, collector-emitter and finally to ground.
The crude but effective method of using 4 diodes drops the 12V source down to 9.2V so that the current limiting resistors maintains the same current through the LED's with either setup(Source or backup).

The light (2.5V, 200mA), what is this for? Do you want to run both ths light and two LED's?

 

something like this? and yes i need this to also power the mystery load.

 

something like this? and yes i need this to also power the mystery load.

Well, between the mystery load and LED's the tiny 9V battery will last less than 2 hours, closer to 1.5V max.

Zener diode 2: When the 9V battery drops below 7.8V it will no longer supply current to the load...to save battery from over discharging.

 

i added in and made a few changes to it now. i remove the third switch between the second zener and transistor as i need to keep it under 2. second i added in a photoresistor and moved my 9v load away so it would only effect the leds.

 

i added in and made a few changes to it now. i remove the third switch between the second zener and transistor as i need to keep it under 2. second i added in a photoresistor and moved my 9v load away so it would only effect the leds.

Don't know what your doing with R2. Q3 needs to be a PNP transistor.

 

I need to add in a photoresistor(R2) to control the two leds.

 

Can't promise you anything...

 

do you think this will also work?

 

do you think this will also work?

All I see changed is the LDR to a variable resistor. That's what a LDR is. With my last circuit, adjusting the 50K variable resistor would tweak how dark it needed to be for the LED's to turn on. Now you will have to manually tweak a resistor to turn the LED's on. Also LED 3 will always be on regardless id the main power is off or not, which adds to the current draw, another 20mA.

 

Well there is no LDR in multisim so i used a variable resistor in place and all i really changed was the 2k connection to between D5 and R3. Is it easy to change led3 to light up only when you are charging? if not then ill just remove it.

 

o 49 ohm 1W should be 47 ohms 0.5W
o The addition of the 1N4002 Diode in series with the 10V zener raises the charge voltage to 10.7V
o charge LED indicator removed
o (4) 1N4001 diodes in series with D1, D2 were removed
o open S3 with S1 closed and battery will run circuit
o open S1 with S3 closed and adapter will run circuit
o Both S1 and S3 closed will be automatic operation, Adapter keeps battery charged and mystery bulb will be on
When dark enough LED's will also be on.

 

woah. i did not expect someone would go through the lenght you did to help someone like me make their first circuit. wish i knew more to contribute to my own project but i do hope this was a good challenge for you as it was for me. your definately the go to person when it comes to battery. much thanks to you and now the fun stuff can begin!

ok. I have double check my value but during my simulation it will only work if S3 is connected. don't know how accurate is multisim but wanted to add this in.

EDIT: i just notice that i forgot to attach ground and now that i did the weird thing is that nothing light up.

 

Perhaps if you have the parts, you could build a test circuit on a bread board. Then you can take real measurements throughout the circuit.