12: Volt Activated Relay Switch

Both a touch and a contact switch are built on one PC board so that the builder can see how each works. A battery can power the contact switch but you'll need an AC power supply for the touch switch to work well. The circuit switches a relay with a 3 Amp

This mini-VOX - voice operated relay - is based on a circuit published in Silicon Chip, 9/1994, p31.

Adjust the sensitivity of this circuit to control a Relay that can turn on whatever is connected to the contacts of the relay. Very practical circuit for a variety of projects. Turn on a light when your dog barks, or set of a siren when an intruder makes

Three relay-based electronic switching circuits that switch according to light levels.

Low cost 12 channel Infrared Remote Control with relay board

Use an old PC as a "dedicated controller" to turn on or off devices lab or radio shack. The circuit includes eight relays controlled with (included) software for either DOS or Windows 3.1. The kit is a boon to the Science Fair project, laborator

There are many applications where you need quick availability of a relay for connection to a particular piece of apparatus. We found in developing our kits that we always needed to have a relay mounted on a PCB within arms reach.

Timer circuits are handy for many experimenters projects, not to mention the photo lab. This kit has three separate circuits that can be used individually or together. Each circuit has a separate 5 Amp relay. Circuits operate on 9 Volt DC.

Use an old PC as a dedicated controller to turn on or off devices lab or radio shack. The circuit includes eight relays controlled with (included) software for either DOS or Windows 3.1. The kit is a boon to the Science Fair project, laboratory experiment

You can program this stand alone controller via PC Serial Port. Simply connect a serial cable from your computer to the connector on relay board.

The most popular use for this kit is to make you own night-light. It can also be used to switch just about any appliance on or off in light or darkness. Light sensitivity is adjustable over quite a range. The relay can handle up to 10 Amps at 110VAC. Oper

You can program this stand alone controller via PC Serial Port. Simply connect a serial cable from your computer to the connector on relay board.

The primary function of this Relay Board is to turn devices on or off. It's simple!

This super cool circuit behaves as a clapper-switch. You clap and the circuit turns on. Clap and it turns off. Great as a light clap switch.

The circuit uses a matched pair of 40 Khz transducer elements to detect movement up to 22 feet away. You may add a relay (not included) to switch higher voltage loads. The unit switches a LED for movement indication. Sensitivity is setable via control. Cr

Timer kits are an ever popular item with the hobbyist. This uses a 555 timer IC and goes from 8 seconds to 8192 seconds.

Power on/off almost anything with this infrared controlled electronic switch. Some spell it Infared!

This circuit is an alarm for the home, car and a lot more. It employs a magnet and reed switch to trigger the circuit. An intergral piezo sounder produces the alarm sound (100dB). There is also a relay capable fo handling up to 10 amps that will switch wh

A very basic power supply that can be adjusted over a range of about 1.5 to 35 volts DC. If you add a heat sink (included), you can run it as hot as 2 Amps output; otherwise about 60 mA @ 12 volts. This is a text book circuit using an LM317, which is a 3

A very basic power supply that can be adjusted over a range of about 1.5 to 35 volts DC. If you add a heat sink (included), you can run it as hot as 2 Amps output; otherwise about 60 mA @ 12 volts. This is a text book circuit using an LM317, which is a 3

A sensitive photo Darlington transistor is used with a CMOS nand gate. The circuit detects light and triggers a siren. You could add your own triac or relay and switch practically anything. The kit uses the MEL12 Darlington super alpha phototransistor, ty