Schmitt Trigger Using BJTs
Category: Transistor Logic
Designer: RANA MUHAMMAD ADNAN KHALIL
Notes
The circuit is simulated in Proteus. You can simulate this circuit in any other simulation software like LTspice or Psim. This is a very simple circuit and a very basic concept of schmitt trigger. 1. To understand this circuit, watch previous circuit "Single Transistor Inverted Schmitt Trigger". 2. Very few components needed to build this circuit. Two transistors and four resistors only. 3. Random input signal is applied at resistor R4. 4. Output is taken from transistor Q2 collector point. 5. On oscilloscope, yellow wave shows output and blue wave shows input which is random signal. 6. This circuit will act as a comparator with hysteresis whose thresholds for setting the output high or low will be defined by the design parameters. 7. The value of thresholds depends on voltage across resistor R3 plus transistor base emitter voltage, which is 0.7V. 8. This value can be changed by changing the value of resistor R3. 9. The working of the circuit is seen in the waveform, which is perfectly fine. More Schmitt trigger circuits will be uploaded soon. Stay with us and share this knowledge with others.