Negative-triggered-touch-circuit

The 4047 is configured as a monostable multivibrator circuit, also known as a one-shot, which is triggered by a negative transition of the signal applied to its pin 6 input. The duration of the multivibrator's output pulse is determined by the values of R1 and C1. Although R1 is specified as a 100 kΩ resistor, it can be varied between 10 kΩ and 1 MΩ. Capacitor C1 can be a nonpolarized capacitor with a practical value above 100 pF. By increasing the value of R4 significantly, the circuit can function as a touch-triggered one-shot multivibrator. Conversely, if the value of R4 is reduced to a lower value, such as 10 kΩ, the circuit can be triggered by a negative pulse through a 0.1 µF capacitor connected to pin 6. With a 100 kΩ resistor for R1 and a 4.7 µF electrolytic capacitor for C1, the output pulse duration is approximately 0.6 seconds. Increasing R1 to 470 kΩ extends the output pulse duration to over 6 seconds.

The 4047 monostable multivibrator is an integrated circuit that can be utilized in various applications requiring a single output pulse in response to a triggering event. The circuit is designed to provide a stable output pulse width that can be adjusted by changing the resistor and capacitor values.

The configuration of the circuit includes the following key components:

1. **R1 (Timing Resistor)**: This resistor plays a critical role in determining the output pulse width. The resistance value can be selected based on the desired timing characteristics, with a range from 10 kΩ to 1 MΩ. The typical value used is 100 kΩ, which produces a pulse width of approximately 0.6 seconds when paired with a 4.7 µF capacitor.

2. **C1 (Timing Capacitor)**: The capacitor works in conjunction with R1 to set the timing interval. A nonpolarized capacitor is recommended for use, with values typically above 100 pF. The choice of capacitor value directly influences the duration of the output pulse.

3. **R4 (Trigger Resistor)**: This resistor can be adjusted to modify the sensitivity of the circuit. A high value for R4 allows the circuit to be activated by a simple touch, making it suitable for applications requiring a touch-sensitive interface. Lowering R4 to around 10 kΩ allows the circuit to respond to a negative pulse from an external source, such as a capacitor connected to pin 6.

4. **Trigger Input (Pin 6)**: This pin receives the negative transition signal that triggers the monostable operation. The design allows for flexibility in how the circuit can be activated, either by a touch or by an external pulse.

The output of the 4047 can be connected to various loads or further circuitry, making it a versatile component in timing applications, pulse generation, and event detection systems. The ability to adjust timing parameters by varying resistor and capacitor values provides designers with significant control over the performance of the circuit.The 4047 is configured as a monostable multivibrator circuit or one shot that is set up to trigger on a negative-transition of the signal applied to its pin 6 input. The multivibrator"s on time is determined by the values of R1 and Cl. Although R1 is shown to be a 100-K unit, its value can be anything between 10 K and 1 MO. Capacitor C1 can be a nonpolarized capacitor with any practical value above 100 pF. By making R4"s value extremely high, the circuit can be used as a touch-triggered one-shot multivibrator.

Ifthe value of R4 is reduced to a much lower-value, such as 10 KO, the circuit can be triggered with a negative pulse through 0.11-" F capacitor connected to pin 6. With a 100-KO resistor for R1, and a 4. 7-flF electrolytic capacitor for C1, the circuit"s on time is about 0.6 second. When R1 is increased to 4 70 KO, the on time of the circuit is increased to over 6 seconds. 🔗 External reference