Help for the project Dark activated lamp

[ericgibbs]

thx for the concern.. Yah i dont have much knowledge in electronics... but i have some in electrical.. ^_^.

since my r7 was blown, isn't it possible to judge that the transistor was reason for the "cannot be turn off problem".. ??
what if the transistors are also affected due to the damage of r7? I still have to test it....

hi,
One point about learning to find a fault in your projects, is to do a step by step check.
Where possible I start at the output stage, if that works OK, move back further into the circuit.
So confirm that the SCR is OK, as I suggested, disconnect the SCR Gate from the circuit and connect it to 0V, the lamp should not light, if it does you have either got a blown SCR or its incorrectly wired into the bridge circuit.

Let us know what you find.

 

[mamand]

ok.... thank you very much.. i'll try it.

 

[mamand]

Hi... Im confused of the pinnings of the pnp and npn transistors.. I have seen the datasheet of those transistors and i found 2 datasheets of them: Philips semiconductor and Fairchild and also they have different pinnings.. Which one should i follow??

 

[ericgibbs]

Hi... Im confused of the pinnings of the pnp and npn transistors.. I have seen the datasheet of those transistors and i found 2 datasheets of them: Philips semiconductor and Fairchild and also they have different pinnings.. Which one should i follow??

hi,
Ref your PM, I understand that the SCR has failed as a short circuit.

Can you confirm which type of transistors you are using on the circuit.??
Do you have an ohm meter.?

 

[mamand]

yes. I have a digital sanwa. The transistors are C33725 and the C32725. The SCR is C106..

I already replaced the 2 transistors, capacitor, and the SCR but it still doesn't off.

Huhu..

I followed the advice of my friend which is, if which of the legs has high resistance from its base it is the collector, and the less resistance is the Emitter and I solder it but the same problem goes again...

I checked the connection once again and it is correct..

Thx 4 ur help.

 

[mamand]

when will you be online again? would you mind having a chat so that we can clarify these things out?

thank you

 

[ericgibbs]

yes. I have a digital sanwa. The transistors are C33725 and the C32725. The SCR is C106..

I already replaced the 2 transistors, capacitor, and the SCR but it still doesn't off.

Huhu..

I followed the advice of my friend which is, if which of the legs has high resistance from its base it is the collector, and the less resistance is the Emitter and I solder it but the same problem goes again...

I checked the connection once again and it is correct..

Thx 4 ur help.

hi,
Whats the resistance of the PT when light and dark.?? What type is it.??

Two datasheets.

 

[ericgibbs]

hi,
This is the circuit running in LTspice simulation.

 

[mamand]

Hey... Share your link for your LTspice simulation download pls. What i used is Multism, it doesn't work well.

 

[mamand]

hi...
In your circuit, you add 47ohms (R9) and 10megohms (R8) and 200(R7)?? I tried my previous circuit in multism simulation and it doens't still off.

I will try your datasheet on transistors.

Thank you very much..

 

[ericgibbs]

hi...
In your circuit, you add 47ohms (R9) and 10megohms (R8) and 200(R7)?? I tried my previous circuit in multism simulation and it doens't still off.

I will try your datasheet on transistors.

Thank you very much..

hi,
I did suggest a 47R in the Gate in an earlier post.
The 10meg is only for the LTspice sim.

I have attached the LTS.asc file you asked for.

 

[mamand]

Hi..

I can't read the file..

 

[mamand]

Hi,,

I followed the datasheet that you have given.. It doesn't solve the problem..

I will try to replace the LDR.

 

[ericgibbs]

Hi,,

I followed the datasheet that you have given.. It doesn't solve the problem..

I will try to replace the LDR.

hi,
The light sensor is a photo transistor. Which type are you using.???

 

[mamand]

Hi,.,.

I remove the LDR from the circuit just to know if the lamp will be on state..

and insert the plug and boom! it was on? Is this normal?

I thought the LDR was the switch for the lamp?

This one is the LDR **broken link removed**

 

[mamand]

Thanks for the help.. ^^

 

[ericgibbs]

Hi,.,.

I remove the LDR from the circuit just to know if the lamp will be on state..

and insert the plug and boom! it was on? Is this normal?

I thought the LDR was the switch for the lamp?

If you remove the LDR the light will go ON.
If you short out the LDR, the light should go OFF.

Normally a LDR resistance falls when lit, as it does so the light will go OFF.

The original circuit diagram shows that the light sensor is a photo resistor, any type.

Tell me what resistance the LDR measures when LIT and when its DARK, measure it when disconnected from the circuit

CAUTION: The circuit is NOT mains isolated.!

 

[mamand]

102.34k-300k ohms small light. with no light it has 10k ohms.

If Bright lights is present it has 500k ohms to 1G ohms.

 

[audioguru]

102.34k-300k ohms small light. with no light it has 10k ohms.

If Bright lights is present it has 500k ohms to 1G ohms.

If it is a Cadmium Sulphide light dependent resistor then it operates backwards.
It is supposed to be a fairly low resistance with light and be a very high resistance in the dark.
It looks like this:

 

[mamand]

Yeah.. Sorry i was wrong. 102.34k-300k ohms small light. with bright lights it has 10k ohms.

with no lights it has 500k ohms to 1G ohms.