# Falstad Circuit - Why is the current still flowing through the transistors?

I'm trying to simulate a simple signal amplifying circuit using three transistors as shown below:

(Note that the LED isn't turned on)

But when I open the switch, the current still flows normally from the 9V source on the left, even though the first transistor's base doesn't receive tension. The current has the same value as before if you look at the bottom right corner. It should be zero.

Here's the image:

I'm very new to electronics and studying it on my own.

• Just to clarify, the 9V source i mention is the one to the right of the LED and the 220Ohm resistor, just before the second switch. Dec 15, 2023 at 15:43
• 10 V applied through the switch without a serial resistor is not really a good thing. And you need also to wire the negative "pole" of this voltage. However, transistors are characterized by a current Icbo (very very low) ... current through transistor with an "open base" ... which explains that you can measure a current ... at least through the diode. Dec 15, 2023 at 16:14
• Also note that because you don't have any ground reference, opening or closing the switch has absolutely zero impact on the circuit. There's nowhere for any current to flow from the +10 V input. Dec 15, 2023 at 16:30
• Presumably you want the negative side of that battery supply to be ground, right? That's where you should put your ground symbol. This is still not a correct circuit, though, because there's no current-limiting on the base of your transistors. Dec 15, 2023 at 16:47
• (With a proper input signal and a base resistor, 220 Ω still was a bit low (assuming 10 V for the battery) and 100 kΩ way high.) Dec 15, 2023 at 20:13