Description: This circuit functions as the inverse of Repeating Timer No. 3. Its operation is constrained to the hours of darkness. The variable resistor (preset) allows for the selection of the darkness level at which the timer will activate.
The circuit is designed to operate exclusively during nighttime conditions, making it suitable for applications such as outdoor lighting control or security systems that require activation only in low-light environments. The core component of this circuit is a light-dependent resistor (LDR), which changes its resistance based on ambient light levels. When the light intensity falls below a predetermined threshold, determined by the variable resistor, the circuit triggers its output.
The variable resistor, or preset, is crucial for calibrating the circuit's sensitivity to light. By adjusting this component, users can set the specific light level that will activate the timer. This adjustability ensures flexibility in various environments, allowing the circuit to function optimally under different conditions.
The output of the circuit can be connected to various devices, such as relays or transistors, which can control higher power loads. This feature enhances the circuit's versatility in real-world applications. For instance, it can be used to turn on garden lights automatically at dusk or activate security lights when it gets dark.
In summary, this circuit provides an efficient solution for controlling devices based on ambient light levels, with the added advantage of user-configurable settings for precise operation in varying light conditions.This circuit is the opposite of Repeating Timer No.3 . Its operation can be limited to the hours of darkness. Again - the variable resistor (preset) lets you choose the level of darkness at which the timer will begin to function..
To initiate the timing process, there are two options available: either connect the START point to ground (GND), in which case the timer activates when connected to the voltage supply, or employ a switch to start the timer.
The timing circuit...
Manufacturers of cordless drills typically recommend a battery charging time of three hours. After this time, the battery should be disconnected from the charger to prevent the risk of overcharging. The following circuit is designed to prevent this scenario by...
Q1 and Q2 create an ALL-ON ALL-OFF circuit that, when in the off state, draws negligible current. P1 initiates the circuit, activating the relay and powering the two integrated circuits (ICs). The lamp is energized through the relay switch, and...
This timer was designed for people wanting to get tanned but at the same time wishing to avoid an excessive exposure to sunlight. A Rotary Switch sets the timer according to six classified Photo-types (see table). A Photo resistor extends...
A switched timer with equal make and equal space periods timing adjustable from over 6 minutes to 38 minutes. This timer circuit is similar to the 5 to 30 minute timer except that when switch S1 is closed, the on/off...
This circuit utilizes a timer to produce pulses at a 5-ms clock rate. The pulses are sequentially shifted into a shift register, illuminating an LED. An auxiliary timer generates one pulse per second to activate the "go" LED and initiate...
The figure illustrates a preset outage timer circuit designed for an electric cooker. The timing range of the circuit extends from 1 hour to 12 hours, adjustable via a potentiometer (PR). The timing mode operates on a counting basis, and...
This electronic timer switch will turn on a light for 100 seconds, turn it off for another 100 seconds, and then turn it on again for 100 seconds after an hour of powering up the circuit. It is a good...
The two circuits illustrated show the operation of opening a relay contact shortly after the ignition or light switch is turned off. A capacitor is charged, and the relay remains closed until the voltage at the diode anode rises to...
We use cookies to enhance your experience, analyze traffic, and (if you allow) serve personalized ads.
By clicking Accept All, you agree to our use of cookies.
Learn more