This is the circuit diagram of TRIAC, SCR and Transistor tester. This is a very simple circuit which can be used for testing of SCRs as well as triacs. The circuit could even be used for checking of PNP and NPN transistors. The circuit works on 3V DC, derived using a zener diode in conjunction… Read More »
Here is the USB printer switch circuit design with two USB input ports and one USB output port. This a really simple device that allow two computers (desktop/laptop) to select a single USB printer or some other USB device, such as an external flash drive, memory card reader or scanner. A rotary switch selects the… Read More »
This is the digital fan speed control circuit design that can be utilize to control the speed of 220V fans using induction motor. The speed control is nonlinear, i.e. in steps. The current step number is displayed on a 7-segment display. Speed can be varied over a wide range because the circuit can alter the… Read More »
This is the circuit design of unipolar stepper motor driver to control unipolar stepper motors with 5, 6 or 8 wires. It uses four MOSFET IRFZ44. This circuit can be operated in free-standing or PC-controlled mode.
If it is desired to connect a video signal originating from a camera or other video source to a normal TV set, you will need this modulator. The audio and video signal is converted into a UHF TV signal so that the signal can be received through the TV antenna input. In certain countries (find… 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 »
The following is an electronic circuit called galaxy audio booster which serves to improve the performance of your audio system. This circuit uses an IC RC4558 in which there are two op-amp modules that can be used for stereo audio applications. The circuit is similar to stereo tone booster that uses the principle of High… 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 »
This 6V and 12V car battery charger circuit can be automatically charged, quickly and correctly, 6V and 12V batteries. Circuit design is divided into two series of modules that are: power supply module and the main charger module containing the regulator modules and direct current amplifier module.