This smoke detector electronic project is designed using LM1801 and common electronic parts. Smoke detector circuit diagram below does not use ionization detection, gas or optocouplers it use two photoresistors (LDR's) and an LED.
Diode D1 rectifies voltage, R7 reducing voltage at a level suitable for integrated circuit.
This simple and inexpensive temperature indicator indicates the temperature of a heat sink in high power circuits can be designed using this electronic circuit diagram.
Temperature is measured by a transistor mounted on a radiator or near power transistor controlled.
This radiator temperature indicator can be designed using electronic circuit diagram bellow .
Temperature indicator consists of two special zener diode, D1 and D2, connected in series to ensure accuracy of 5.96 V Zener voltage at 25 ° C.