Free electronic circuit design and schematic diagram
LM56 is a monolithic thermostat designed for simple temperature control. The chip has two programmable threshold that can be used to drive a fan and or alarm. Here is the schematic diagram of the fan control circuit: The circuit will turn on the fan when the temperature rise above 50 Celsius degree, and this threshold is set by the voltage […]
Read more
Light dimmer circuit is used to control the lamp for arbitrary brightness. This dimmer circuit work for incandescent lamp, not a fluorescent one. The dimmer circuit here work for both 110V and 220V AC. Here is the schematic diagram of the circuit: Dimmer Wiring Diagram The dimmer circuit is wired in series with the lamp, you can say the dimmer […]
Read more
This circuit is another radio frequency (rf) field strength meter, similar with our previous field strength meter circuit, but with lower supply voltage (only a single cell 1.5V battery). Here is the schematic diagram of this rf strength meter circuit: To use, turn on transmitter and meter; adjust C1 for peak reading. Turn off transmitter and adjust R1 for a […]
Read more
This instrument is very useful for radio frequency (rf) engineer and hobbyist, especially when he/she has to adjust the final rf transmission. Setting up an antenna impedance matcher is one of the example. Here is the schematic diagram of this rf meter circuit: The circuit use only one transistor (MPSA18) as the active component. The signal strength meter display uses […]
Read more
Speed control for dc motor (electric motor) can be implemented using open loop or closed loop. Closed loop controller, also known as servo controller, or a feedback control, gives the best performance since the loop will maintain the actual speed to follow the reference. In simple application, an open loop controller can be enough if the load is constant, such […]
Read more
Electric motor has been widely used as motion control, and many type of motor controllers have been designed to provide variable speed drives for the motor. The best controller is the servo controller, where a precise speed control is implemented using a speed sensor in the feedback path. The circuit of the motor controller in this article use a novice […]
Read more
Thermocouples give many benefits compared to thermistor/RTD (Resistance Temperature Devices). Some advantages of thermocouple are their wider temperature range, their reliability, and their consistency over long period of time. In some cases, thermocouple calibration is even unnecessary. Thermocouple temperature sensors are widely used in temperature controllers for boilers, oven, pressurized reactor, even in high temperature furnace. A general purpose temperature […]
Read more