Could someone explain this circuit PLEASE.

[breneer]

Dear Sir,

Honestly, I'm not a engineer. And I just want to know if someone explain this circuit.

**broken link removed**

*HOW THE CIRCUIT WORKS*
- SIGNAL DIODE
- CAPACITOR
- RESISTOR
-TRANSISTOR



THANK YOU VERY MUCH!

 

[IanP]

First of all, there is an error on the drawing: -V is obviously +V ..

There are 4 identical blocks in this circuit, so lets concentrate on block 1 build around transistors T3 and T8 (to small print to read)..
When SW1 is closed current flows through D3, R23 and D11 to the Base of T8 putting T8 into saturation. Voltage on its collector goes low and current flows through LD1 - R13(Iguess) and D4. So, LED LD1 is ON and all theree other circuits are disabled by D4. Because of low potentiol on the collector of T8, T3 starts to conduct current which lifts up potential on R23 thus latching this circuit, section 1 that is ..
To reset you have to remove power from the circuit and this is done by shutting down transistor T1 (its base is pulled up to V+).
After reset button is released voltage is fed back ..

Whichever section of the circuit is activated (latched) this turns on LED LD5 as lower potential on the base of T6 turns this transistor ON ..

Regards,
IanP

 

[breneer]

Other Question: How can I connect a relay booster?
**broken link removed**
From the (block 1) LED to relay. Where does the input connected and the ground.
Is it to the ( input -connect --> anode of LED ) and (ground --connect--> cathode of LED)

 

[IanP]

Connect R1 from relay booster circuit to the collector of T3 (either side of R23 will do) .. and ground to ground ..
Regards,
IanP

 

[breneer]

Well, My 2N3904 keeps on defecting. When I replace it, its okay but when I test it again, its defected.

Should I replace it with higher transistor.
What transistor specs. ?