Digital Audio/Video Input Selector
Need to connect more than one audio-video (AV) source to your colour television? Don’t worry, here’s an AV input expander for your TV. It...
Multiple Applications of High-Power LEDs
Nowadays, high-power light-emitting diodes (LEDs) LXHLMW1C are available in the market. These white LEDs contain indium-gallium-nitrogen (InGaN). The LEDs’ emitting capacity is 20 candela...
Pencell Charge Indicator
Small-size AA cells and button cells used in electronic devices providing a terminal voltage of 1.5V are normally rated at 500 mAh. As the...
9-Line Telephone Sharer
This 9-Line Telephone Sharer circuit is able to handle nine independent telephones (using a single telephone line pair) located at nine different locations, say,...
Audio Amplifier for Personal Stereo
In the output stages of most broadcast receivers and some amplifiers, there is a limit up to which maximum power can be developed without...
Solidstate Remote Control Switch
Here is a solidstate remote control switch which uses readily available electronic components. The control circuit comprises the transmitter and receiver sections. The range of...
Stabilised Power Supply with Short-Circuit Indication
Here is an efficient 4-stage stabilised power supply unit for testing electronic circuits. It provides well regulated and stabilised output, which is essential for...
Digital Stop Watch
Here’s a digital stop watch built around timer IC LM555 and 4-digit counter IC with multiplexed 7-segment output drivers (MM74C926).
IC MM74C926 consists of a...
Under-/Over-Voltage Beep For Manual Stabiliser
Manual stabilisers are still popular because of their simple construction, low cost, and high reliability due to the absence of any relays while covering...
Watchman Watcher
Here is a circuit that can be used in offices, stores, warehouses, etc during night to check whether the watchman of your establishment is...
