Free Circuit Diagram

The large issue today that caused by more electronic equipment enters the home and the office is noise of fan. to reduce fan noise, a variable speed fan is used because it permits quieter and slower, fan speed when temperature conditions allow. To build a variable speed fan we can use digital control or high-speed/low-speed [...]

We usually use a fan to manage the temperature, but it produces audible noise at full speed. To reduce this noise we can use this circuit. The first circuit reduces the noise by controlling the cooling-fan speed as a function of temperature. It uses an IC that combines temperature sensing with a PWM output. When [...]

Thermoelectric cooler (TEC) or Peltier cooler is becoming popular because of its robustness and maintenance free characteristic. Here is one example of a linear thermoelectric cooler (TEC) driver circuit. This driver  is capable of delivering ±2A into a TEC. This circuit operates on a single +5V supply and drives the TEC in the most preferred [...]

The temperature of a quartz crystal for oscillator should to be kept constant to operate at very stable frequency. This oven temperature controller is suitable for such purpose.  Here is the schematic diagram of the temperature control circuit:

Although this circuit is small and simple, the design use a PWM output to preserve the efficiency.  The [...]

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 [...]

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 [...]