This article is for 50Hz Square Wave Generator Circuit using Transistors.
Two transistors switch ON and OFF one by one.
No IC is used only simple parts are required.
We can change resistor or capacitor to change speed.
This circuit is good to learn basic oscillator working.
Circuit Working:
Parts List:
| Components | Value | Quantity |
|---|---|---|
| Resistors | 10k 1/4 watt | 2 |
| 1k 1/4 watt | 2 | |
| Preset 220k | 2 | |
| Capacitors | Ceramic 0.1µF | 2 |
| Semiconductors | NPN Transistor BC547 | 2 |
| Battery / Power Supply 12V DC | 1 |
When power supply is ON the circuit start by itself.
Due to small difference, one transistor turn ON first.
Its output become active and other transistor stays OFF.
Capacitor connected to ON transistor start charging.
After some time the capacitor discharge to other transistor base.
This make second transistor ON and first transistor OFF.
Now second capacitor start charging.
After delay, it discharge back and turn first transistor ON again.
This switching continue again and again.
Because of this, square wave output generate and both outputs work opposite time.
How to Build:
To build a 50Hz Square Wave Generator Circuit using Transistors follow the below connection steps:
- Assemble all parts as per circuit diagram.
- Emitter pin of Q1 and Q2 both connect to ground.
- Collector of Q1 connects with R1 and C1.
- Collector of Q2 connects with R4 and C2.
- Base of Q1 connects with C2 and VR1 through resistor R2.
- Base of Q2 connects with C1 and VR2 through resistor R3.
- R1 and R4 connect from +12V to collectors.
- VR1 and VR2 connect from +12V to transistor bases.
Conclusion:
This is simple and low cost 50Hz Square Wave Generator Circuit using Transistors.
Only basic parts used and circuit is easy to make and understand.
Output frequency depends on resistor and capacitor.
By changing RC value, different frequency we can get.