- How i can calculate the output power on pin 3 on each 555 Timer.
- I don't know how to calculate the Base Resistance on the transistor.
Just *NO*!
Instead, power both 555s all the time and use the two minute timer 555 to hold the LED flasher 555 in reset before and after the two minute on time.
There are other simplifications and improvements that can be made - e.g. a CMOS 555 can generate a reasonably accurate 50% duty cycle waveform with only a single resistor and capacitor for the timing network
Doctorandus's comments about the base drive don't go far enough. When driving a BJT as a switch, you almost always want it to saturate to minimize the Vce voltage drop and thus minimize its dissipation. Any noob can take a 2N3904 and calculate a base resistor that provides *just* enough current for an ideal 2N3904 to saturate, and a slightly more savvy noob will know that hFE drops off at high collector currents so will use the use the min. hFE from the datasheet, and if multiple values are listed pick one at a collector current similar to their application, but due to component tolerances and other factors its advisable to have at least DOUBLE the mimimum calculated base current, and you will find that most datasheets that give data for the transistor in saturation do so with the condition that Ib shall be 10% of Ic to guarantee hard saturation. If you can afford the excess base current, this is a good rule of thumb to follow for your own designs, so for a 50mA load on Ic, you'd want 5mA Ib. The output of a 555 IC built of BJTs rather than MOSFETs (i.e. a clone of the original NE555) doesn't swing rail-to-rail, and under load is typically about 2V less than the supply, so your base resistor is probably only going to have about 10V across it when on. Therfore choose an E24 series 2.0K resistor or if all you've got is E12, choose 2.2K. The base current will probably be a bit under 5mA unless you use a CMOS 555 which do have rail-to-rail outputs, but the Ib=Ic/10 rule of thumb has plenty of safety margin.
i make a schematic using two 555 timers, One monostable and one astable, i want one led blinking (one second on, one second off) for two minutes.
Have you thought about using a microcontroller like the Arduino UNO board?
PD. Or an Arduino Nano:
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=arduino+nano&_sacat=0
TerraByter seems to have little experience with electronics, hence my advice on the Arduino.
for Ian.M, I challenge you to explain to me the advantages of using two 555s compared to an ATTINY202 in this case
Costing just few cents,
For a beginner an Arduino is better.
No good. Disch2 will short the supply when it activates. To fix it, remove the link to Vcc and transfer the top end of the associated resistor to Out2, leaving Disch2 n/c. You can also link the two Cont pins and save a capacitor.
Also, when posting schematics here, make sure each component has a unique reference designator. Multiple resistors and capacitors all labelled 'R?' and 'C?' is useless as when we need to refer to a specific part of your circuit, and more than one also has the same value, its ambiguous.