Solve Circuit Puzzle: 2 Current Sinks

[SAlex]

Hi to everybody!

I've next schematic, but i don't know how it's works in details.

The capacitor in the left upper corner is charged in the beginning. Then go 0-level to C15 and turn on first current sink (VT16 VT17). tnen 1-level to C15 turn off first sink. Then start works second (VT18).

Can u help me ?

 

[berkeman]

Hi to everybody!

I've next schematic, but i don't know how it's works in details.

The capacitor in the left upper corner is charged in the beginning. Then go 0-level to C15 and turn on first current sink (VT16 VT17). tnen 1-level to C15 turn off first sink. Then start works second (VT18).

Can u help me ?

Welcome to the PF.

Is this question for schoolwork? I can move it to the Homework Help forums if it is.

What is the context of the question and this circuit? The circuit diagram is incomplete as far as I can tell. Where are the signal sources? Where are the input and output terminals? What is the load for the output? Where does the dangling cap at the bottom go?

 

[SAlex]

That's full schematic in PCAD-2006 and image

 

[SAlex]

Brief description: connector XP1 (1,3,5,7 pins) is sensors. 21 and 23 - lithium battery. L1 throught VT3 out pulses to corresponding sensor, which is selected by switch on transistors. Then out signal goes to amplifier, and needed level is detected by comparator. But i need to know how is working current sinks in right bottom corner. First sink on VT16, VT17 - and second on VT18. They discharge C18. Sorry for my poor english )))