LDR resistance

[oginne08]

How can i lower the resistance of an LDR?

Maybe something like in a light activated circuit?

I just need a circuit that's like this, Light falls on the LDR, then just shorts the circuit.

The resistance of the LDR that i bought was too high, it couldn't short the circuit.

 

[Nigel Goodwin]

You need electronics to make it do what you want, LDR's on their own are pretty useless.

Exactly what you need depends on exactly what it has to do, and you're giving no information on your requirements,

 

[ericgibbs]

How can i lower the resistance of an LDR?

Maybe something like in a light activated circuit?

I just need a circuit that's like this, Light falls on the LDR, then just shorts the circuit.

The resistance of the LDR that i bought was too high, it couldn't short the circuit.

hi,

LDR's are not designed to drive another device/load directly, its required that a transistor or simple amplifier is used between the LDR and the 'load'.

 

[oginne08]

hi,

LDR's are not designed to drive another device/load directly, its required that a transistor or simple amplifier is used between the LDR and the 'load'.

You need electronics to make it do what you want, LDR's on their own are pretty useless.

Exactly what you need depends on exactly what it has to do, and you're giving no information on your requirements,

"I just need a circuit that's like this, Light falls on the LDR, then just shorts the circuit."

A simple circuit, i need it to use for an external flash with my camera. The LDR will be mounted on my camera's built-in flash, then as the flash fires, it triggers the LDR to short the connecting leads on the external flash, so that the external flash fires too.

 

[Nigel Goodwin]

So you want a slave flash trigger, it's a VERY common circuit - a little bit of electronics and usually an SCR to trigger the slave flash.

Here's one example https://www.electro-tech-online.com/threads/digital-slave-flash-trigger.23122/