Speaker Protection Circuit (Stereo)

This is the speaker protection circuit, provides stereo speaker protection and prevents switch-on clicks and DC components on the output of the amplifier connected.

Digital Tachometer / RPM Meter

This is the circuit diagram of Digital Tachometer / Digital RPM Meter which can be used for cars or motorcycles with 2 and 4 stroke petrol engines with any number of cylinders and contact breaker or electronic ignition systems. May be used as a general purpose revolution counter. Digital Tachometer Mainboard Scheme:

Digital DC Voltmeter based ICL7107 Chip

Here is the schematic diagram of digital DC voltmeter built based IC ICL7107. The power supply for this circuit is +5V. You may use 9V battery and then use regulator IC LM7805 to achieve 5V stabilized voltage. This circuit will be good to display your power supply output.

230V Automatic Night Lamp

This is the circuit diagram of 230V automatic night lamp based photo resistor to sensing the light environment. When the condition is dark enough, the one or more lamps will be turned on and when the condition is bright enough, then the lamps will be turned off.

Clap On / Off Switch

This is the circuit diagram of Clap On / Off Switch. The circuit allows you to operate your lighting or any circuit device which use 24V / 3A maximum supply, simply by clapping your hands. It has a relay output that can be used to turn external devices on/off.  This circuit is good and ideal for… Read More »

Traffic Baton with Bulb or LED Flasher

This is the traffic baton circuit which available in two versions that are traffic baton with LED flasher and traffic baton with bulb flasher. Both the circuits powered with a 6V, 4.5Ah rechargeable battery, which is clipped to the operator”s waistband. This circuit which come from EFY mag, will help the police or someone to… Read More »

Smart Sensitive Electronic Hearing Aid

This is the circuit diagram of electronic hearing aid featured with sensitive sound detection and energy saving, so this hearing aid will work in the long term with a 9V batery battery cycle. The common hearing aid circuits consume the battery energy continuously once they are turned on. This smart electronic hearing aid saves battery… Read More »

6V / 9V / 12V Battery Charger with Constant-Current Charging

This is the circuit diagram of battery charger which has many important features such as current-constant charging, overcharge protection, short-circuit protection, deep discharge protection and more. The constant-current charging is a popular method for lead-acid and Ni-Cd batteries. In this circuit, the battery is charged with a constant current that is generally one-tenth (1/10) of… Read More »


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