Thanks !hi mishra,
You are a LTSpice user, why not use the Power option in LTS.?
BTW: You need to add the parameters of the transistor [ or use an equivalent model] to get a true reading.
How can you calculate PD of the transistor, in that circuit, if you do not state the specification of the actual transistor.
Also all the details of the square wave drive signal.
Thank you so much !find the current through the transistor and voltage drop with input high and low,
that gives you two powers
Define the high / low time of your input , that gives you a ratio,
the ratio then allows you to calculate the power
so if when high, you dissipated 1 watt, and when low, 0.1 wat
and you were high for 10 % of the time,
then power is 10% * 1 watt + 90% * 0.1 watt = 0.19 watt
Thanks i understand that why it is always ON.hi,
You have a 8.4V supply.
Q2 Base Emitter is say 0.7v
So across the 2k2 there is 8.4V - 0.7v = 7.7v
I via the 2k2 is ~3.5mA
The bias resistor 47k and 47k on Q1 means that it is always conducting, the 4V signal input will not turn Off Q1 as its Emitter is at 8.4V.
What are you trying to do with that circuit, it is ......
For your reference, this is the LTS with the LTS model and an equivalent real model.
hi,Power across Q1 is 3mV but still i wanted to do math for power across Q1.
Thanks you much for your all support !
You are missing the point I raised, it is only 3.5mW on each High level, but its only at the High for 50% of the time.!
So your value needs to be 3.5mW/2
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