Imagine two whispers one with little louder.
Op-amp is smart listener and it hears only the difference and ignores background noise; also it makes small difference bigger using voltage gain.
Hence, this Simple Op-Amp Circuit helps boost weak signals in electronics.
Circuit Working:
Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | 6.8k | 1 |
| 4.7k | 1 | |
| 1k | 1 | |
| 100k | 1 | |
| 68k | 1 | |
| 1M | 1 | |
| Capacitors | Ceramic 33nF | 1 |
| Ceramic 4.7nF | 1 | |
| Electrolytic 4.7µF | 1 | |
| Semiconductors | Transistor BC547 | 2 |
| Transistor BC557 | 1 | |
| LEDs Red 5mm 20mA | 2 |
This circuit uses 3 transistors to make simple op-amp, as it work like class A, and AC amp gain to about 5000; but we can use it like normal op-amp.
Output stays near half of power supply and this happen because of voltage drop on 2 LEDs with input transistor and 1M resistor.
Also, 68k resistor and 4.7nF capacitor stop it from oscillate and we can use this op-amp as filter or oscillator with 1k load.
Furthermore, it gives good square wave at 10kHz and drops 3dB at 50kHz.
How to Build:
How to Make a Simple Op-Amp Circuit need to follow the below mentioned steps for connections:
- First, connect input to base of first BC547 with 33nF cap and 100k resistor and connect emitter of this BC547 to point between 4.7k resistor and 2 LEDs in series.
- Then 4.7k resistor goes to positive and LEDs goes to negative.
- Now connect base of BC557 to collector of BC547 using 68k resistor.
- Next, put 6.8k resistor between BC547 collector and positive.
- After that, connect emitter of BC557 to positive and then put 4.7nF cap from base of BC557 to ground.
- Also, connect collector of BC557 to base of second BC547 output and emitter of this BC547 go to ground.
- Then connect its collector to positive with 1k resistor and also connect this collector to output using 4.7uF capacitor.
- Lastly, connect 1M resistor from output BC547 collector to input BC547 base.
Note:
- We can change parts like resistors, capacitors to match our needs but be careful while working with circuits.
Conclusion:
Overall, this How to Make a Simple Op-Amp Circuit is good for learning, as it shows how op-amps boost signals and controls voltage.
Also, we can make filters, amplifiers and more and try different values to learn more and get better at electronics.