Simple Automatic Water-Level Controller
Water level controllers are common nowadays. The automatic water level controller described here is built around a timer NE555 and inverter buffer CMOS IC...
PROGRAMMABLE DOOR- BELL WITH FLASHING LEDS
IC1 (NE555) is used here as a clock generator. It is configured as an astable multivibrator whose frequency can be adjusted with the help...
SHORT WAVE TRANSMITTER
This transmitter circuit operates in shortwave HF band (6 MHz to15 MHz), and can be used for shortrange communication and for educational purposes.
The circuit...
Auto Reset Over/Under Voltage Cut-Out
This over/under voltage cut-out will save your costly electrical and electronic appliances from the adverse effects of very high and very low mains voltages.
The...
7MHz CW/AM QRP TRANSMITTER
The circuit of a 7MHz C W / A M QRP transmitter described here can be used to transmit either CW or audio frequency...
RAMP CONTROLLED LIGHT
The circuit described here can be used for controlling a decorative lamp from zero intensity to maximum intensity in a specified time. Typical applications...
SENSITIVE TEMPERATURE SWITCH
This temperature switch has high sensitivity and is quite reliable. Here, in place of a single transistor, a Darlington pair has been used for...
CLAP SWITCH
Here’s a clap switch free from false triggering. To turn on/off any appliance, you just have to clap twice. The circuit changes its output...
2-LINE INTERCOM CUM- TELEPHONE LINE CHANGEOVER CIRCUIT
The circuit presented here can be used for connecting two tele phones in parallel and also as a 2-line intercom.
Usually a single telephone is...
MAGIC LIGHTS
The circuit as shown in the figure employs 14 bi-colour (red and green) LEDs having three terminals each. Different dancing colour patterns are produced...
