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Increase the amperage fo PNP transistor

Harald Kapp

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correct, I'd wrongly assume that 0.69 is the result deducted from main source.
So what is the actual value? Measured.
FYI, I'd need to cascade with three pnp transistor to form as darlington stage to be able to produce the 340 mA (as ready measured) before it could be able to drive the motor.
Makes no sens. Again, show us the circuit diagram so we can understand what you are doing.

Also make sure you haven't swapped emitter and collector in the actual circuit.. When you swap emitter and collector, the transistor may seemingly work but with much lower current gain.
upload_2022-2-19_19-30-6.png
 

koklimabc

Sep 7, 2013
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So what is the actual value? Measured.

Makes no sens. Again, show us the circuit diagram so we can understand what you are doing.

Also make sure you haven't swapped emitter and collector in the actual circuit.. When you swap emitter and collector, the transistor may seemingly work but with much lower current gain.
View attachment 54293
Circuit.jpg
I decided to add "Boost Buck Converter" (By adjust the output voltage to 7 volt and at output of collector pin in connect in within motor and a series of three LED).
 

Harald Kapp

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How do you expect us to help if you don't provide the answers we request?
 

koklimabc

Sep 7, 2013
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So what is the actual value? Measured.

Makes no sens. Again, show us the circuit diagram so we can understand what you are doing.

Also make sure you haven't swapped emitter and collector in the actual circuit.. When you swap emitter and collector, the transistor may seemingly work but with much lower current gain.
View attachment 54293
For three LED It is actually 6.66 volt (each of it is 2.2 volt), FYI, I'm using PNP transistor because the output pin of LM393 is worked out connect to Ground (That is negative side), so it must using PNP for features to be triggered as switch on negative.
 

Harald Kapp

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Check the 1 kΩ resistor from the output of the comparator to the base of the transistor. Make sure it is truly 1 kΩ, You may have inadvertently used a much higher value in the real circuit. 3 transistors really shouldn't be necessary, a single one should suffice. The Darlington arrangement has the disadvantage that the voltage to the load (motor and LEDs) is reduced due the additiona VBE required to drive the several stages of transistors.
Check also the correct connection of emitter and collector, cf. post #21.
 

koklimabc

Sep 7, 2013
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Check the 1 kΩ resistor from the output of the comparator to the base of the transistor. Make sure it is truly 1 kΩ, You may have inadvertently used a much higher value in the real circuit. 3 transistors really shouldn't be necessary, a single one should suffice. The Darlington arrangement has the disadvantage that the voltage to the load (motor and LEDs) is reduced due the additiona VBE required to drive the several stages of transistors.
Check also the correct connection of emitter and collector, cf. post #21.
kk, noted.
 

Audioguru

Sep 24, 2016
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mAh is a measurement of capacity, as @crutschow mentioned. Your measurement surely is 6 mA. It is a bit on the low side, I would have expected something around 8 mA (given the 1 kΩ base resistor and the Vbe of the transistor), but 6 mA is not unreasonable. A 2N2907 has a minimum DC current gain of 50 which allows for up to 300mA collector current from 6 mA base current.
How much current actually flows depends on the load. What are the specs of the motor and the LEDs?
Current gain is not used when a transistor is used as a switch. For 350mA output then the datasheet says the base current must be 35mA or more. The LM393 has a minimum output current of only 6mA and the 1k base resistor limits the output current even more.
 

WHONOES

May 20, 2017
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What is actually happening to your motor. Does it never start, never turn off something in between or none of these?
 
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