This is the circuit diagram of two tones train horn which built based dual timer IC NE556. The circuit is quite simple and easy to built and of course inexpensive. The circuit diagram is in a “basic” design, you may try to modify this circuit, for example: use a low power audio amplifier and use… Read More »
Equaliser circuits typically divide the audio spectrum into separate frequency bands and have independent gain control for each band. The output of each band is mixed at IC4(A) and then fed to an audio power amplifier. Proper quality factor (Q) needs to be selected to avoid overlap in adjacent bands as this introduce colouration into… Read More »
Here is the simple and low cost mosquito repellent circuit design. The circuit serves to keep the mosquitoes out of the room or the location where the device is installed. According to certain publications, the frequency emitted by the male mosquitoes is said to be around 20—25 kHz, and so within the realm of ultrasound.… Read More »
Here the circuit design of vibration sensor alarm. Initially, when power switch S1 is flipped to “on” position, power indicator LED1 lights up immediately. IC LM555 (IC1), wired as a simple latch circuit with control input, is powered and R-C components R4 and C5 connected at its reset pin 4 force the latch to standby… Read More »
This is a simple and low cost dew sensor circuit that can be used to switch off any gadget automatically in case of excessive humidity. Dew (condensed moisture) adversely affects the normal performance of sensitive electronic devices. The main part of this circuit is a low cost dew sensor element (resistor type). Although dew sensor… Read More »
This is the circuit diagram of 5VDC single polarity to 12VDC dual polarity converter based on IC LM2595-12 from National Semiconductor. This circuit will convert 5V DC single voltage (+) become 12V DC dual polarity output (+), GND, (-).
This battery charger circuit is regulated and adjustable to make this circuit able to charge the mosto NiCAD battery. This adjustable regulated battery charger circuit will work for single cell or multi battery cell which connected with series/parallel connection. The maximum voltage of the batteries should be 18V maximum. Power transistors Q1 and Q2 are… Read More »
This is the electronic circuit diagram of aquarium temperature probe capable to monitor the temperature of water and indicate the rise in temperature through audio-visual indicators. This circuit uses diode 1N34 as the temperature sensing probe. The resistance of the diode will be vary depends on the temperature in its vicinity.
This is the ultrasonic distance detector or sonar ranging system which can be used for general purpose. There are kit version available on the market, but of course the price is 3x more expensive than if you build your own sonar ranging system. Some application may use this circuit such as robot applications, body height… Read More »