Resistor circuit to increase .4m amp to 12 m amp

could anyone help me out plssss. the output of 7404n is .4m amp and the base current required for tip120 is 12m amp. the output of 7404n cannot drive base of tip120. so could anyone come up with a resistor ckt to increase the current plssssssss.

Re: .4mamp to 12 m amp

Hi,
You can connect the output of 7404n which gives 0.4m amp current to a Pull-up resistor with a value 2.2K to 4.7K and connect to input of TIP120. You can try this.
The required current will be drawn from the Pull-up resistor which is connected to VCC.

In case you need more details, don't hesitate to contact me.

Regards,

N.Muralidhara
MSRS, CRL-BEL

Re: .4mamp to 12 m amp

There are several things you can do ..
One option is to connect a 300-ohm-pull-up resistor between the output of the 7404 gate and +5V ..
Gate can sink of up to 16mA, and resistor can deliver roughly 12mA to the base of TIP120 ..
You also need a base resistor, connected between the output of the gate anf the base of the TIP, but its value can be quite low, say, 22Ω-47Ω ..
That's if you used just one gate (1/6 of the sn7404n) ..

If other gates are not used you can consider connecting them in parallel ..
HT or HCT series can be connected directly in parallel, sn7404n gates should have each its own pull-up resistor and base resistor, so form the base of the tip point of view, it will "see" several resistors, each injection it's share of the base current ..

Regards,
IanP

Re: .4mamp to 12 m amp

only one resistor that is pull up is sufficient and nothing else.wat is vcc.is it that of the 7404n.