- This topic has 1 reply, 2 voices, and was last updated 1 year, 11 months ago by Michael.
2019-November-11 at 11:49 #7466LectronFanModerator
Hi everybody !
Time to pick up our start and expansion set again and combine 2 already published circuits to build a Divider and Random generator !
I was tinkering about this since I conceived the Toggle flip flop but I struggled with a correct functioning.
Now I know why ! The relay had no diode inside and the induction spikes disturbed the whole circuit !
So, I proudly present you a circuit which divides a clock pulse in 2 and can also be used as a random generator.
The whole design fits on a A3 mounting board and uses almost every Lectron cube of our Basic and Expansion set !
We have also 2 controls which shape the clock pulse. From short to large and from slow to fast. This pulse is made visible on the meter (I know Michael is also fond of the meter, so let’s use it !)
The toggle Flip Flop divides this pulse in 2 and the lamp will make this visible.
As you see in the diagram, I used a 120 Ohm resistor to protect the relay. The advantage of putting this at the emitter of T1 lies in the fact that C1 will see a higher impedance. So it will charge and discharge slower.
The meter has also an advantage in the circuit. It discharges C2 when the relay is not activated (rest position). Try to remove the meter and replace it with a corner block. See now what happens with the toggle Flip Flop.
The lamp has it protection resistor of 47 Ohm and even a diode.
To operate the circuit is fairly simple :
When you press the button, the clock circuit around T1 and relay start to operate.
Turning P1 counter clockwise will make the pulse slow
Turning P2 counter clockwise will make the pulse wider.
If you turn P1 fully clockwise and P2 fully counter clockwise, you have a random generator !
With each press of the button will or will not make the lamp glow ! You can use this as a coin toss !
And oh, by the way, this circuit can’t be constructed with the legacy PNP transistors with build in resistors. These resistors stop the whole Flip Flop from toggling 😕
Here’s the diagram :
- This topic was modified 1 year, 11 months ago by LectronFan.
- This topic was modified 1 year, 11 months ago by Michael. Reason: Changed font and size styling for easier reading
2019-November-13 at 08:39 #7477MichaelKeymaster
Very cool Professor Frank! Thank you so much 🙂
- This reply was modified 1 year, 11 months ago by Michael.
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