I agree..The CM1820 light bulb draws only 0.1A at 28V, not 3A.
This circuit has a 24V supply and the saturation voltage loss of the darlington and 4.7 ohm resistor produces only 22.5V across the light bub then its current is only about 85mA and the darlington dissipates (1V x 85mA)= 85mW and will not be warm.
If the supply for the Cmos gate is 12V then the base current is (12V - 1.4V)/62.9K= 0.17mA. Then an MPSW45 darlington should saturate pretty well when its output is (0.17mA x 500)= 85mA.
Did you try this?The 60k resistor is causing the transistor's base and collector current to be lower, which, paradoxically, can increase the power dissipation of the transistor. Try shorting out the 60k and see if the heating problem disappears.
No.Hi audioguru,
I didnt understand the point you are trying to make here. Are u suggesting to supply the transistor 12 V instead of 24V?
Look at the datasheet for the Cmos HCF4025B NOR gate."CMOS GATE" where is that???
See Post #13:No.
You were asked in post #9 "What is the supply voltage for the NOR gate?" but you did not answer.
So I am just guessing that it is +12V. The maximum allowed supply voltage for the HCF4025B Cmos NOR gate is +18V, not +24V.
The circuit should work and the MPSW45 should be barely warm when the gate has a supply between +12V and +18V.
Look at the datasheet for the Cmos HCF4025B NOR gate.
The Supply on the NOR gate is 18V and on the original NOT gate it is 10V.
by Jake Hertz
by Duane Benson
by Jake Hertz
by Duane Benson