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...