Humidity Detector Circuit
by P. Marian in Alarms |
This humidity sensor consists of 2 copper conductors that are located at small distance from each other. The relay switches as soon as the moisture makes a connection that is more or less electrically conductive between the 2 electrodes. How does the humidity detector works? When the electrical resistance between the 2 sensors...
Simple Touch Light Switch Circuit
by P. Marian in Lights |
This is a very simple touch light switch circuit that uses the 4011 IC, one transistor and a relay. The C1 capacitor stores the switching state at a certain time and is charged or discharged according to the output signal of N1 gate. When the sensor is touched this state is returned to the input of N1 gate and so there is a...
High Voltage Converter Circuit
by P. Marian in Power supply |
Starting from a 30 volt power supply this high voltage converter circuit can deliver a voltage between 0 to 3 kV (version 1) or from 0 to 10 kV (version 2). IC 4011 gates N1 … N3 are connected as astable multivibrator that commands the Darlington T1/T2 with an rectangular impulse of 20 kHz. The transistors cannot be...
4011 IC Datasheet
by P. Marian in Datasheets |
The HEF4011B is a quad 2-input NAND gate. The outputs are fully buffered for the highest noise immunity and pattern insensitivity to output impedance. It operates over a recommended VDD power supply range of 3 V to 15 V referenced to VSS (usually ground). Unused inputs must be connected to VDD, VSS, or another input. The...
Door Ajar Alarm Circuit
by T.K. Hareendran in Alarms | Tested |
Ever accidentally left your front door ajar and had a pet escape? Here is a smart solution to this problem. The circuit is fairly simple but a great example of using a tiny circuit to get the job done. All you need is a CD4011 IC plus a handful of components. In this door ajar alarm/beeper circuit, a bar magnet-reed switch...
Cheap Metal Detector Circuit
by P. Marian in Measure |
The working principle of this cheap and easy to build metal detector circuit consists in mixing two equal frequencies which causes a low-frequency interference. When one of the oscillators become unstable then the frenquency of the interference will be modified. The metal detector circuit is built with CD4011. The oscillator...
Touch Switch Circuits
by P. Marian in 555 | Various |
Here is a great collection of touch switch circuits. A touch switch is an electronic device that enables us to control a circuit by simply touching a sensor. Simple touch switch circuit with 4011 – source The circuit as you can see from its diagram is very simple and only uses 8 components. The heart of the circuit is...
Digital Volume Control Circuit
by P. Marian in Audio |
The heart of this digital volume controller DVC circuit is IC2 4067, 16-channel analog multiplexer. Because the 1kΩ has been connected between every input and output, the multiplexer can act like a potentiometer. The total resistance is 15kΩ . You can use different values for the resistor to obtain a different characteristic....
Digital Tachometer Circuit for Bikes
by P. Marian in DIY | Measure |
This DIY digital tachometer for bikes uses two reed switches to get the speed information of the bicycle. The reed switches are installed near the rim of the wheel where permanent magnets pass by. The permanent magnets are attached to the wheelspokes and activate the reed switches everytime they pass by it. The speed is...
Electronic Potentiometer Circuit
by P. Marian in Various |
This is a digitally controllable electronic potentiometer. The heart of the circuit is a 16 channel analog multiplexer. Controlled by the BCD value at the inputs, the output pin of the multiplexer (pin 1) is connected to any one of the 16 outputs. The output pins are connected with 1k resistors. The IC2 can therefore be...