Friday, March 27, 2015

Rain Detector Alarm

This is the circuit diagram of rain detector alarm. When the sensor is wetted with the water, then the alarm will be activated. This circuit can be used for other purposes.

A 555 astable multivibrator is used here which gives a tone of about 1kHz upon detecting water. The sensor when wetted by water completes the circuit and makes the 555 oscillate at about 1kHz. The sensor is also shown in the circuit diagram.

Tuesday, November 18, 2014

Two Tone Electronic Siren Circuit


This is the circuit diagran of two tone electronic siren. The scheme is simple and easy to built, it based on two ICs with different task: produce audio signal and amplify the audio signal.

List of Components:

R1-R2-R3: 2.2KΩ
R4: 1KΩ
R5: 10K (potentiometer)
R6: 470Ω
C1 - C2: 10 uF
C3 - C4: 470 nF
C5: 10 uF
C6: 220 uF
IC1: Integrated Circuit TTL 7400
IC2: LM386
Z1: Zener 5 volts 1/2 watt
Speaker 8 Ω

Thursday, June 19, 2014

PWM Controller Circuit using SN75603 and SN75604

Here the circuit diagram of PWM Controller which uses complementary half-H peripheral drivers SN75603 and SN75604, with totem-pole outputs rated at 40 V and 2.0 A. These drivers effectively place the motor in a full-bridge configuration, which has the ability to provide bidirectional control.