Can anyone please explain why totempole outputs should not be connected together what is the solution

 

If you tie two totem-pole outputs together, they will "fight to the death" if they are set to different logic levels.

You can use diodes from each output with a pull-up or pull-down resistor, depending on the logic you want.

You can tie open-collector outputs together and use a pull-up resistor to create a wired AND gate.

 

i am srry but wats a pull down resistor

 

A pull-down resistor has one end connected to the low voltage in the circuit; in the case of TTL and CMOS, that is usually ground or Vss.

A pull-up resistor has one end connected to +V, Vcc or Vdd.

 

Thnks bro!