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This circuit controls a load (in this case a dc brushless fan) based on a temperature compared with a setpoint. THe transduced is a diode in the forward polarization regime. In fact when forward biased, the forward voltage drop accross a diode has a temperature dependance, in particular has a negative linear(ish) slope. This because of the boltzmann distribuition, causing electrons to pass to the conduction band thermically, lowering the voltage drop accross the diode.... [read more]

This circuit is intended to let the user turn off a lamp by means of a switch placed far from bed, allowing him enough time to lie down before the lamp really switches off.... [read more]

This circuit is a temperature controlled version of Repeating Timer No.3 . The light dependent resistor has been replaced by a temperature dependent resistor or thermistor. And a small preset potentiometer lets you choose the temperature above which the timer will operate.... [read more]

This circuit provides a delayed visual indication when a door bell switch is pressed. In addition, a DPDT switch can be moved from within the house which will light a lamp in the door bell switch. The lamp can illuminate the words "Please Wait" for anyone with walking difficulties.... [read more]

The LME49830 EF125WT1 amplifier PCB module showcases National Semiconductor’s LME ultra-high fidelity power amplifier input stage ICs (drivers). The LME49830 is a fully complementary bipolar 200V input stage IC with 56mA (typical) of output current that has been optimized for audio applications. With 56mA of current drive, the IC can drive numerous power transistors to achieve high levels of output power. The LME49830’s ultra-low distortion and low-noise, combined with a user adjustable compensation scheme results in a tightly controlled, but highly dynamic listening experience.... [read more]

This i-TRIXX circuit can prevent a whole lot of trouble for those of you who go on holiday in a caravan. It would be a significant damper on your holiday spirit when you are ready to leave the camping and discover that you have used your battery too much and that you are now unable to start the car. This annoyance can be avoided if you were warned early enough by an illuminated LED when the charge in the battery threatens to become too low.... [read more]