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Switching a TIP41 Directly from the output of a 741 IC

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RodneyB

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I have made a daynight switch for my LED solar lights and have been switching a relay through a BC547 transistor.

I have included a time delay by doing the following

From the output (pin 6) through a 30K resistor a 470μF capacitor is charged. A 100K resistor feeds the base of a BC547 which turns on a 12 Volt relay.

For the sake of Space I want to take out the 12Volt relay and substitute it for a TIP41.

My question is will i be able to substitute the BC547 with the TIP41 ( Naturally observing the pin spacings are not the same) Or will I have to have the BC547 to turn on the TIP41.

Many thanks in advance for the help.
 
hi Rodney

I assume the relay is in the collector circuit of the BC547.??

I would suggest that the BC547 and the TIP41 could be connected as a Darlington pair.

Do you have simple circuit showing the voltages and values of the existing circuit.? also how many LED's are you using,?
 
A better device for switching the LEDs would be a NFET. It is voltage operated at its gate and will not load the 741 output.

btw-a 741 is not very good for anything when used at voltages less than ~12V; get a modern opamp.
 
A better device for switching the LEDs would be a NFET. It is voltage operated at its gate and will not load the 741 output.

btw-a 741 is not very good for anything when used at voltages less than ~12V; get a modern opamp.

What is a more moden op amp?
 
What is a more moden op amp?
A 741 opamp is 45 years old. It was designed to use only a 30V supply and work at DC and low frequencies. It is noisy.
There are thousands of much newer and better opamps available almost anywhere.
But we do not know where you are.
 
...

Do you have simple circuit showing the voltages and values of the existing circuit.? also how many LED's are you using,?

I second the question. Also what is the sensor, and the supply voltage?
 
I will post the diagram a little later, I am based in Zimbabwe, we have 3 electronic shops which carry reasonable stock, failing that I import what I need from South Africa from RS Components, Mantech Electronics and Communica. I have a friend in England who sends me things from Maplin when I need and I sometimes purchase from China.
 
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