2n3565

[Hercan Robotics]

Is there an equivalent for the 2N3565 Transistor?

 

[audioguru]

Are you making the Simple Lie Detector project? It works with any little NPN transistor: 2N2222, 2N3904 or BC547 pops into my mind.

Make it with a 9V battery:

 

[Hercan Robotics]

Cant find a 3K resistor can i use something else?

 

[audioguru]

3k is a standard 5% resistor value. Two 1.5k resistors in series makes 3k. A 1.2k and a 1.8k in series makes 3k, and many other series and parallel combinations.
But that simple circuit will also work with 3.3k resistors.

 

[Nigel Goodwin]

3k is a standard 5% resistor value.

Depends on your definition of 'standard', it's NOT a standard E12 value.

 

[Hero999]

No, it's an E24 value.
https://www.pc-control.co.uk/resistor-eia.htm

 

[Nigel Goodwin]

No, it's an E24 value.

I know!

 

[audioguru]

I haven't used resistors with a silver tolerance band since "carbon composition" days. Everywhere I shop for 5% resistors has the entire E24 values.

 

[Hero999]

Most hobyists don't bother to stock the entire E24 series. E12 values are so much more common and you can buy 1% tolletence resistors in kits containing E12 values.

I have an E12 series set of 1% tollerence metal film resistors from 10hm: to 1Mhm:, plus many more of the E6 values from 1hm: to 10Mhm: and even more of the E3 series; all are 1% tollerence metal film.

 

[Hercan Robotics]

I know this is the wrong place to post but I have built the lie detector circut and the needle on the meter goes the wrong way( past zero). Do I have somthing backwards?

 

[audioguru]

I think it is normal for that stupid simple circuit to show the meter needle pointing backwards when the probes aren't connected to anything so the transistor is turned off. With skin between the probes the meter should show near zero and you can adjust the pot for zero. Short the probes or have sweating skin and the needle will move forward.

 

[Hercan Robotics]

Shorting the probs or toching the probs does not make any change.

 

[Hercan Robotics]

Could I have the meter backwards.

 

[audioguru]

I hear an echo. Are you Robdude on Aaron's forum?
You fried your transistor by using it to short your batteries before.

 

[Hercan Robotics]

Yes I am Robdude. I was just trying to get the quickest reply. Alright ill replace the transistor and see what happens.

 

[Hercan Robotics]

Ok I replaced the transistor and its doing the same thing. Could the transistor be backwards? What about the meter? Can I send a pic how?

 

[audioguru]

During your reply here, click on Manage Attachments. Then click on Browse and double click on your pic or schematic. Then click on Upload. Then Submit Reply.

 

[Hercan Robotics]

ok here are the pics.

 

[Hercan Robotics]

the LED on the right is just a power indicator circut for my breadboard.

 

[audioguru]

I can't see where the battery wires are connected and can't see which connects to what.
Look at the datasheet for the 2N3904 to see its pins.