Exit Delay For Burglar Alarms Circuit
The circuit operates by utilizing a capacitor (CI) that charges to the supply voltage when switch SI is depressed. This action effectively biases transistor Q1 on, facilitated by bias resistors R2 and R3, which are configured to provide the necessary base current to Q1. The charging of CI creates a voltage that remains present throughout the delay period, which serves to temporarily disable the alarm circuit, preventing it from triggering during this designated time frame.
The delay time can be adjusted by modifying the value of capacitor CI. Increasing the capacitance will result in a longer delay, as it takes more time to charge to the supply voltage. Conversely, decreasing the capacitance will shorten the delay time, allowing the alarm circuit to activate more quickly after SI is released. This flexibility in timing is essential for applications where precise control over alarm activation is required.
Resistors R2 and R3 play a crucial role in determining the biasing conditions for transistor Q1. The values of these resistors can also be adjusted to fine-tune the biasing level, impacting the overall response time of the circuit. Proper selection of these components ensures that the transistor operates within its optimal range, thus maintaining reliability and efficiency in the circuit's performance.
In summary, this circuit design allows for adjustable delay times through the manipulation of capacitor CI and the biasing resistors, facilitating effective control over the alarm system's activation. Depressing SI charges CI to the supply voltage. This biases Ql on via bias resistors R2 and R3. A voltage is available for the duration of the delay period, to hold off the alarm circuit. CI can be increased or dccrcascd in value to alter the delay times.
Related Circuits
The most challenging aspect of interpreting ladder diagrams, particularly for individuals familiar with electronic schematic diagrams, is the representation of electromechanical relays. The operation of a motor control circuit should be explained, detailing what occurs when the "Run" switch...
A preamplifier in the audio frequency range amplifies a noisy audio signal to drive a diode clipper. Suitable audio input levels would be in the 10-mV to 1-V range. The audio preamplifier circuit is designed to enhance weak audio signals, typically...
The electronic dog repellent circuit diagram below is a high-output ultrasonic transmitter primarily intended to act as a dog and cat repeller. The electronic dog repellent circuit utilizes a high-frequency ultrasonic transmitter to emit sound waves that are unpleasant to...
The Sixteenth Street control circuit consists of a secondary decoding output control circuit. Each output terminal of the sixteen decoding is connected to a bistable circuit made up of dual D flip-flops (CD4013). A DC relay is connected to...
A whip antenna measuring between 30 to 50 cm is capable of receiving signals from 10 MHz to over 220 MHz. The circuit incorporates a BF981 dual-gate MOSFET (T1), which offers low noise characteristics, high input impedance, and enhanced performance. The...
Men often appreciate the convenience of television remote controls, which can sometimes frustrate their female partners. They tend to switch channels frequently, wanting to ensure they do not miss anything while a specific program is on. With the remote...