Build a simple, soft-action muting switch

The circuit in Figure 1 adds a soft muting switch with power-up and power-down muting to a line-level audio circuit. R4, C1, and JFET Q1 quietly ground a signal in 100 to 200 msec when you close S1 or release it when you open S1.

Switching Solenoid Driver

It operates by PWM - well, actually by PFM - Pulse Frequency Modulation. At power up, C1 charges up via D1 and R1. R2 will conduct, pulling the base of the emitter follower, Tr2, up and feeding gate voltage to the MOSFET.

USB-Sensing Mains Power Switch

Do you have to manually switch your PC peripherals on (and later off again) each time you boot your PC? If so, this project will make life a lot easier. It monitors your PC USB port and automatically turns all that other gear on and off as required.

Ultrasonic switch

C ircuit of a new type of remote control switch is described here. This circuit functions with inaudible (ultrasonic) sound. Sound of frequency up to 20 kHz is audible to human beings.

Basic Solid State Relays

These Relays would be ideal for applications where many relays are needed and the load current requirements are low. Due to their small size a large number of relays could be mounted on a single printed circuit board. The relays are based on a 4N33 Optoisolator package. This device has a Darlington output transistor and as the first figure shows it can be used alone for low power applications of up to 30Ma.

Fast Acting Electronic Circuit Breakers

The circuit breakers on this page make use of the Zetex - ZXCT1009 "High Side Current Monitor' integrated circuit. The circuits have variable trip current settings and are designed for low current applications.

10 relay board for LPT-16-0

There are 10 relays DPCO(dual pole change over), which are activated using a 12V supply, and around 60mA current.

3-way & 4-way switches

Controlling a light or lights with two or more switches

Alternating On-Off Switch

Hand Clap Electronic Control

turn relay on and off by hand clap.