Fade-In & Fade-Out Effects to the In-Car Lights

This circuit adds a nice fade-in fade-out visual effects when switching your in-car lights on and off. The fading time can be changed by adjusting the charging and discharging times of the capacitor.  To do this, adjust the values of the 10 KOhm and 4.7 MOhm resistors.

Solid State Solution for Driving 2x55W Automotive Bulbs

This circuit provides a fully protected, 100% automotive proof, low voltage and low consumption proposal for driving additional (or existing) 2x55W bulbs (high beams). Superior ruggedness and reliability is offered by means of a pure Solid State Switches solution.

LDR & LED Pair Smoke Detector and Alarm by LM1801

Circuit is connected to the mains directly. D1 rectifies the alternating source and R7 reduces it to the level that the circuit can operate with.  C2 capacitor stabilizes the voltage and zener inside the IC regulates it.

Ultrasonic Burglar Alarm

Transmitter and receiver parts of the circuit are connected each other by using a triple cable. System operates with 20V supply and 10V effective output voltage drives the ultrasonic transducer at its highest value.

500Hz Modulated Ultrasonic Transmitter

Ultrasonic oscillations which are generated by unmodulated ultrasonic transmitters commonly for remote control are usually affected from other ultrasonic sources in the media and that's why we are giving a 500Hz modulated ultrasonic transmitter circuit here.

High Voltage Protector for Meters by CA3130

Normally, in a digital voltmeter, high input impedance of the preamplifier stage is protected against very high voltages by two diodes. One of them is connected to the positive terminal and the other one is connected to the negative terminal of the power supply.