Use this simple current stabilizer, which works witch different loads without adjusting:

View attachment 323796

Is the 3V, 7V and 10V load is where load is suppose to be attached? What is the circuit call? Also can you explain how the circuit works and how your getting resistor values?

 

Is the 3V, 7V and 10V load is where load is suppose to be attached? What is the circuit call? Also can you explain how the circuit works and how your getting resistor values?

Yes, 3 V Load1, 7 V Load2 and 10 V Load3 are your loads.

Minimal BF of TIP29C is 40, so for Ic=200 mA base current
should be more than 200/40=5 mA, therefore 1 kΩ value of resistor R1
is selected, which provides about 10 mA base current for Q2.

Circuit call is "Current stabilizer"

V forward of B-E Q1 is 720 mV, so value of R2 at desired current 200 mA
should be 720/200=3.6Ω.

 

Yes, 3 V Load1, 7 V Load2 and 10 V Load3 are your loads.

Minimal BF of TIP29C is 40, so for Ic=200 mA base current
should be more than 200/40=5 mA, therefore 1 kΩ value of resistor R1
is selected, which provides about 10 mA base current for Q2.

Circuit call is "Current stabilizer"

V forward of B-E Q1 is 720 mV, so value of R2 at desired current 200 mA
should be 720/200=3.6Ω.

So I would get 12V at where you have :V load or I get 3V????

 

So I would get 12V at where you have :V load or I get 3V????

When you deal with LEDs as load, forget about voltages!
Use only currents.
On your "3V, 200mA load" at current 200mA automatically will 3 V.
On your "7V, 200mA load" at current 200mA automatically will 7 V.
On your "xV, 200mA load" at current 200mA automatically will x V.

 

When you deal with LEDs as load, forget about voltages!
Use only currents.
On your "3V, 200mA load" at current 200mA automatically will 3 V.
On your "7V, 200mA load" at current 200mA automatically will 7 V.
On your "xV, 200mA load" at current 200mA automatically will x V.

I want to make sire I am using below. I am using two in parallel so 200mA.

when I tirned my voltage to 12V it flicker on and off and then yellow part was damaged. So I dont see how led depend only on current?


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when I tirned my voltage to 12V it flicker on and off and then yellow part was damaged.
So I dont see how led depend only on current?

For LEDs:
Rule 1: Never put voltage on LED, only provide desired current through it.
Rule 2: Never connect LEDs in parallel, only connect them in series, if needed.
ADDED:

also I dont see any models TIP29C LTSpice. Where can I get one?

.MODEL TIP29C npn(IS=2.35E-18 NF=886M NR=886M RE=370M RC=1 RB=10 VAF=40 VAR=20 ISE=19.8F ISC=19.8F ISS=0 NE=1.5 NC=1.5 NS=1 BF=513 BR=5 IKF=195M IKR=195M CJC=131P CJE=131P CJS=0 VJC=515M VJE=515M VJS=750M MJC=330M MJE=330M MJS=0 TF=53.1N TR=6.9U EG=1.11 KF=0 AF=1)
ADDED:

I am using two in parallel so 200mA.

If you are using 100 mA LEDs, change value of R2, R4, R6 to 7.2 Ω.

 

Use this simple current stabilizer, which works witch different loads without adjusting:

View attachment 323796

also I dont see any models TIP29C LTSpice. Where can I get one?

 

also I dont see any models TIP29C LTSpice. Where can I get one?

I think you're going to have issues if you use a power supply less than 12V. The power transistors will need a beta higher than 40.

The circuit I posted is more complex, but it will work with a supply of 5-12V.

 

I think you're going to have issues if you use a power supply less than 12V. The power transistors will need a beta higher than 40.

The circuit I posted is more complex, but it will work with a supply of 5-12V.

Can you change R1 1k to 300 ohms and it should work for 3bdc to 12vdc in that circuit with beta of 40?

 

For LEDs:
Rule 1: Never put voltage on LED, only provide desired current through it.
Rule 2: Never connect LEDs in parallel, only connect them in series, if needed.
ADDED:

.MODEL TIP29C npn(IS=2.35E-18 NF=886M NR=886M RE=370M RC=1 RB=10 VAF=40 VAR=20 ISE=19.8F ISC=19.8F ISS=0 NE=1.5 NC=1.5 NS=1 BF=513 BR=5 IKF=195M IKR=195M CJC=131P CJE=131P CJS=0 VJC=515M VJE=515M VJS=750M MJC=330M MJE=330M MJS=0 TF=53.1N TR=6.9U EG=1.11 KF=0 AF=1)
ADDED:

If you are using 100 mA LEDs, change value of R2, R4, R6 to 7.2 Ω.

I understand voltage is not consideration here but do you have some simple circuit for stable voltage as well?

 

I understand voltage is not consideration here but do you have some simple circuit for stable voltage as well?

The kind of circuit that would be reasonable depends on a number of factors, including what the voltage is, what the range of currents that must be supported, how stable it needs to be and over what conditions, as well as other factors like needed efficiency and size and cost constraints.

 

The kind of circuit that would be reasonable depends on a number of factors, including what the voltage is, what the range of currents that must be supported, how stable it needs to be and over what conditions, as well as other factors like needed efficiency and size and cost constraints.

Ok i will just start new thread since in this circuit voltage is not an issue.

 

I understand voltage is not consideration here but do you have some simple circuit for stable voltage as well?

Simplest circuit:


TL431A: https://aliexpress.ru/item/10050055....productlist.search_results.15.50c966adxKLCwb
EDIT:

For what metric of "simplist"?

You are right. Sentence eliminated.

If Vin = Vout + Vbe, the circuit won't work -- where's the base current for the transistor coming from?

Ask authors of datasheet, please.

 

Simplest circuit:

View attachment 323812
TL431A: https://aliexpress.ru/item/10050055....productlist.search_results.15.50c966adxKLCwb

For what metric of "simplist"?

If Vin = Vout + Vbe, the circuit won't work -- where's the base current for the transistor coming from?

 

Voltage regulator circuit

 

Simplest circuit:

View attachment 323812
TL431A: https://aliexpress.ru/item/10050055....productlist.search_results.15.50c966adxKLCwb

Can you please explain how the circuit works and how each resistor capcitor values are derived? Also where is vref?

 

So, V1 does not vary from 3V to 12V. It is switch selectable from 3V to 12V.
Set the switch to 12V and you are done with that.
Use a 47Ω 1/2W resistor in series with the 200mA LED.

Its not that simple. I also then need transistor circuit which would turn off the current supply when I have solar panel voltage above 0.5vdc and turn on when I have 0.5vdc and below.
If i use what you said above then how can I build such transistor circuit without ics only using resistors inductors capacitors and transistors and diodes?

 

Can you please explain how the circuit works and how each resistor capcitor values are derived? Also where is vref?

Study datasheet TL431-D.PDF. It will answer your questions.

 

Its not that simple. I also then need transistor circuit which would turn off the current supply when I have solar panel voltage above 0.5vdc and turn on when I have 0.5vdc and below.
If i use what you said above then how can I build such transistor circuit without ics only using resistors inductors capacitors and transistors and diodes?

Why this particular restriction on devices? Why no ICs?

How critical is the 0.5 V threshold? If it turns on and off at about 0.6 V or 0.7 V, is that close enough? If not, why not?

How much hysteresis do you need? Or is it okay for the LED to flicker as the solar panel output approaches the threshold?

What is the actual range of supply voltages that the circuit must operate over without modification?

 

What is this "Landscape" thing you keep referring to, and what is its relationship to the varying different voltages (5V, 7V, etc)? We need a better explanation!