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I've been looking for a simple LED fade in/fade out circuit when power is turned on/off for a 12 V LED. I have tried the following circuits but the problem is that I can't reach the full brightness of the LED that it reaches when simply connected to 12 V power supply.

I think it is due to the resistor which connects the capacitor to VCC. It allows the capacitor to charge slowly and show fade in effect, but also limits the current and thus max output voltage. I have tried altering the component values but if I decrease the value of the resistor the fade in effect gets faster.

Please help me with this.

EDIT :-

(Sorry for not mentioning these points before).

1. Ignore the resistor and the series of led on the emitter of Q1 in circuit 1 (replace it with a load capable of taking 12v).

R1 is 4.7K, R2 is 33K, C1 is 1000uf, Q1 is BC548 in circuit 1.

2. In circuit 2 (the one with 100k resistor), I've tried altering the values of the resistors to a point where the 100k resistor were 100 ohm but even though the brightness increases the fade in time decreases a lot.

3. Don't worry about the fade in/ fade out time being same. I just need a good fade in effect and don't care about the fade out.

4) WHAT I NEED IS - I just need a circuit at the output of which the voltage goes from 0 to 12v when power is on and from 12 to 0v when power is off. Please suggest me a new circuit if this is not possible with the ones below.

Thanks...

^{simulate this circuit – Schematic created using CircuitLab}

I've been looking for a simple LED fade in/fade out circuit when power is turned on/off for a 12 V LED. I have tried the following circuits but the problem is that I can't reach the full brightness of the LED that it reaches when simply connected to 12 V power supply.

I think it is due to the resistor which connects the capacitor to VCC. It allows the capacitor to charge slowly and show fade in effect, but also limits the current and thus max output voltage. I have tried altering the component values but if I decrease the value of the resistor the fade in effect gets faster.

Please help me with this.

EDIT :-

(Sorry for not mentioning these points before).

1. Don't worry about the fade in/ fade out time being same. I just need a good fade in effect and don't care about the fade out.

2) WHAT I NEED IS - I just need a circuit at the output of which the voltage goes from 0 to 12v when power is on and from 12 to 0v when power is off. Please suggest me a new circuit if this is not possible with the one below.

Thanks...

^{simulate this circuit – Schematic created using CircuitLab}

I've been looking for a simple LED fade in/fade out circuit when power is turned on/off for a 12 V LED. I have tried the following circuits but the problem is that I can't reach the full brightness of the LED that it reaches when simply connected to 12 V power supply.

I think it is due to the resistor which connects the capacitor to VCC. It allows the capacitor to charge slowly and show fade in effect, but also limits the current and thus max output voltage. I have tried altering the component values but if I decrease the value of the resistor the fade in effect gets faster.

Please help me with this.

EDIT :-

(Sorry for not mentioning these points before).

1. R1 is 4.7K, R2 is 33K, C1 is 1000uf, Q1 is BC548.

2. Don't worry about the fade in/ fade out time being same. I just need a good fade in effect and don't care about the fade out.

3) WHAT I NEED IS - I just need a circuit at the output of which the voltage goes from 0 to 12v when power is on and from 12 to 0v when power is off. Please suggest me a new circuit if this is not possible with the ones below.

Thanks...

I've been looking for a simple LED fade in/fade out circuit when power is turned on/off for a 12 V LED. I have tried the following circuits but the problem is that I can't reach the full brightness of the LED that it reaches when simply connected to 12 V power supply.

I think it is due to the resistor which connects the capacitor to VCC. It allows the capacitor to charge slowly and show fade in effect, but also limits the current and thus max output voltage. I have tried altering the component values but if I decrease the value of the resistor the fade in effect gets faster.

Please help me with this.

EDIT :-

(Sorry for not mentioning these points before).

1. Ignore the resistor and the series of led on the emitter of Q1 in circuit 1 (replace it with a load capable of taking 12v).

R1 is 4.7K, R2 is 33K, C1 is 1000uf, Q1 is BC548 in circuit 1.

2. In circuit 2 (the one with 100k resistor), I've tried altering the values of the resistors to a point where the 100k resistor were 100 ohm but even though the brightness increases the fade in time decreases a lot.

3. Don't worry about the fade in/ fade out time being same. I just need a good fade in effect and don't care about the fade out.

4) WHAT I NEED IS - I just need a circuit at the output of which the voltage goes from 0 to 12v when power is on and from 12 to 0v when power is off. Please suggest me a new circuit if this is not possible with the ones below.

Thanks...

^{simulate this circuit – Schematic created using CircuitLab}

I've been looking for a simple LED fade in/fade out circuit when power is turned on/off for a 12 V LED. I have tried the following circuits but the problem is that I can't reach the full brightness of the LED that it reaches when simply connected to 12 V power supply.

I think it is due to the resistor which connects the capacitor to VCC. It allows the capacitor to charge slowly and show fade in effect, but also limits the current and thus max output voltage. I have tried altering the component values but if I decrease the value of the resistor the fade in effect gets faster.

Please help me with this.

EDIT :-

(Sorry for not mentioning these points before).

1. Ignore the resistor and the series of led on the emitter of Q1 in circuit 1 (replace it with a load capable of taking 12v).

R1 is 4.7K, R2 is 33K, C1 is 1000uf, Q1 is BC548 in circuit 1.

2. In circuit 2 (the one with 100k resistor), I've tried altering the values of the resistors to a point where the 100k resistor were 100 ohm but even though the brightness increases the fade in time decreases a lot.

3. Don't worry about the fade in/ fade out time being same. I just need a good fade in effect and don't care about the fade out.

4) WHAT I NEED IS - I just need a circuit at the output of which the voltage goes from 0 to 12v when power is on and from 12 to 0v when power is off. Please suggest me a new circuit if this is not possible with the ones below.

Thanks...

I've been looking for a simple LED fade in/fade out circuit when power is turned on/off for a 12 V LED. I have tried the following circuits but the problem is that I can't reach the full brightness of the LED that it reaches when simply connected to 12 V power supply.

I think it is due to the resistor which connects the capacitor to VCC. It allows the capacitor to charge slowly and show fade in effect, but also limits the current and thus max output voltage. I have tried altering the component values but if I decrease the value of the resistor the fade in effect gets faster.

Please help me with this.

EDIT :-

(Sorry for not mentioning these points before).

1. R1 is 4.7K, R2 is 33K, C1 is 1000uf, Q1 is BC548.

2. Don't worry about the fade in/ fade out time being same. I just need a good fade in effect and don't care about the fade out.

3) WHAT I NEED IS - I just need a circuit at the output of which the voltage goes from 0 to 12v when power is on and from 12 to 0v when power is off. Please suggest me a new circuit if this is not possible with the ones below.

Thanks...