Stable states: Two stable states
Working idea:
• Press Trigger (S₁) —> Output goes high
• Press Reset (S₂) —> Output goes low
• Output remains in that state until next input.
Stable states: Two stable states
Working idea:
• Press Trigger (S₁) —> Output goes high
• Press Reset (S₂) —> Output goes low
• Output remains in that state until next input (bistable
behavior).
• No press —> Holds state
The charging and discharging currents of a capacitor are exponential waveforms. The charging current decreases from its maximum value to zero, while discharging current flows in the opposite direction and decreases to zero.
Charging —> Positive exponential decay (V/R to 0)
Discharging —> Negative exponential decay (- V_o/R to 0)
Process: Set your DMM to "Diode test" mode. Identify the transistor's three terminals, for example BC547 i.e., base, collector, and emitter by using its part number and datasheet. Connect red probe to base and black probe to collector/emitter, you get ~ 0.6-0.7 V (result forward bias). This means an NPN transistor is OK.
Reverse the probes give us no reading (i.e., OL).
Note: If you get 0.00 V (or a beep) in both directions, the transistor is likely shorted means it is a bad transistor. If you get OL in all cases, it is likely opened means it is a damaged transistor.
Important: If you're testing a transistor while it's still on the circuit board, other components can affect the reading. For a reliable test, remove the transistor or disconnect at least one leg.
Charging: Current starts at maximum positive value and exponentially falls to zero.
Discharging: current reverse direction and the magnitude of current decreases exponentially toward zero.
How can an LED be finger controlled?
Components required:
24 V relay, 8 × LEDs (i.e., 4 × 🔴 LEDs & 4 × 🔵 LEDs),
2 × resistors (i.e., 220 ohm & 330 ohm), a capacitor (i.e., 1000 microfarad, 25 V), connecting wires, breadboard, and supply source (i.e., 15 V DC)
Supply voltage = 5 V
2N3904 BJT is used in this circuit.
2N3904 BJT is used in this LDR circuit.
If Resistor = 100 kilo ohm & Capacitor = 10 micro farad
Then,
Time Constant = RC = 1 s
And,
Full charge/discharge time ≈ 5(Time Constant) ≈ 5 s