unhappy
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Knowing Indian market I suggested the use of darling-ton transistor. but if you try with SL100/Cl100/n100 it can be achievedWhy didn't you look at the datasheet of the 2N3904 to see that its maximum allowed current is only 200mA and its performance above 100mA is poor?
The maximum output current of a 2N2222, 2N4401 and hundreds of other transistors is 600mA or more and will work much better. The base resistor should be 180 ohms.
Why didn't you look at the datasheet of the 2N3904 to see that its maximum allowed current is only 200mA and its performance above 100mA is poor?
The maximum output current of a 2N2222, 2N4401 and hundreds of other transistors is 600mA or more and will work much better. The base resistor should be 180 ohms.
The 2N2222 is very old. I have a Philips datasheet with it in a metal case.
There are thousands of modern transistors and ICs here in The West. Maybe there are only a few old ones (maybe not made anymore) in your country.so suggest me some other one please
There are thousands of modern transistors and ICs here in The West. Maybe there are only a few old ones (maybe not made anymore) in your country.
I have never seen a 2N2222 transistor or an SL100 transistor that are common in your country.
I think I saw a 741 opamp about 40 years ago.
There are thousands of modern transistors and ICs here in The West. Maybe there are only a few old ones (maybe not made anymore) in your country.
I have never seen a 2N2222 transistor or an SL100 transistor that are common in your country.
I think I saw a 741 opamp about 40 years ago.
You did not show your schematic of the circuits that did not work with 2n3055 and SL100 transistors so we cannot help you fix them.
Nobody makes an IRF44 Mosfet so no datasheet is made for it.
Your attachment 103553 does not work.
With a 12V supply, the typical output high voltage from a 555 driving a 2N4401 emitter-follower transistor with 40mA is +10.5V. The typical output of the emitter-follower with a 400mA load is only +9.5V. But the voltage losses can be much higher.
If the 555 drives the 2N4401 transistor as a switch (common-emitter, look in Google) with a base current of 40mA and a load current of 400mA then the load typically gets 11.75V.
If the 555 drives an IRFZ44 Mosfet as a common-source switch then the 400mA load gets 11.99V. The LEDs WILL NOT be dimmed unless the contacts on your breadboard have a high resistance.
It is all shown on the datasheets.
The contacts on a breadboard are designed for low current and frequently are corroded or weakened.
I use parts soldered on stripboard for most of my prototypes.
Didn't you see my reply about it in post #30?
Didn't you see my reply about it in post #30?
I said: A Mosfet has a high gate-source capacitance that slowly ramps its turn on time when its is turned on by a resistor as high as 560 ohms. Then it heats up during the ramping. The heating will be less when the gate is driven from an NPN-PNP pair of emitter-followers as shown earlier in this thread.
Didn't you see my reply about it in post #30?
I said: A Mosfet has a high gate-source capacitance that slowly ramps its turn on time when its is turned on by a resistor as high as 560 ohms. Then it heats up during the ramping. The heating will be less when the gate is driven from an NPN-PNP pair of emitter-followers as shown earlier in this thread.
With that mosfet, the load should be connected to Vcc, drain to load, source to ground. That is a "low" configuration. Otherwise, you need to boost the gate voltage to Vcc + 10V (+/-).
In the "high" configuration you describe, when the mosfet turns on, the voltage drop across it is very low. Therefore Vsource ≈ Vdrain ≈ Vcc. Thus, the gate must be >>Vcc if Vgs is to be 10V.
As you point out, there are a lot of circuits on the Internet, and it can be confusing. It is even more confusing when we don't know the circuit you are actually using. Please post the mosfet circuit you are actually using at this point.
John
You said you used the Mosfet as a source-follower with the drain at Vcc and the load from the source to ground. Then it is not a switch and needs a very high gate voltage. Then you posted a correct schematic that you did not use.
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