Welcome!

The circuit will give us 10 amps (12 amps surge) with performance that equals or exceeds any commercial unit. The circuit even has a current limiting feature which is a more reliable system than most commercial units have.... [read more]

The sunset lamp comes on at full brightness and then slowly fades out over 1.5 hours time and stays off until power is recycled.... [read more]

Typically the op-amp's very large gain is controlled by negative feedback, which largely determines the magnitude of its output ("closed-loop") voltage gain in amplifier applications, or the transfer function required (in analog computers). Without negative feedback, and perhaps with positive feedback for regeneration, an op-amp essentially acts as a comparator. High input impedance at the input terminals (ideally infinite) and low output impedance at the output terminal(s) (ideally zero) are important typical characteristics.... [read more]

Normally home appliances are controlled by means of switches, sensors, etc. However, physical contact with switches may be dangerous if there is any shorting. The circuit described here requires no physical contact for operating the appliance. You just need to move your hand between the infrared LED (D2) and the phototransistor (Q1). The infrared rays transmitted by D2 is detected by the phototransistor to activate the hidden lock, flush system, hand dryer or else. This circuit is very stable and sensitive compared to other AC appliance control circuits. It is simple, compact and cheap. Current consumption is low in milliamperes. The circuit is built around an IC CA3140, D2, phototransistor and other discrete components.... [read more]

This Keypad is suitable for the Modular Burglar Alarm. However, it has other applications. Pressing a single key will energize the relay. Entering the Four-Digit code of your choice will de-energize it.... [read more]

It’s entirely logical that low-cost miniature microcontrollers have fewer ‘legs’ than their bigger brothers and sisters – some-times too few. The author has given some consideration to how to economise on pins, making them do the work of several. It occurred that one could exploit the high-impedance feature of a tri-state output. In this way the signal produced by the high-impedance state could be used for example as a CS signal of two ICs or else as a RD/WR signal. All we need are two op-amps or comparators sharing a single operating voltage of 5 V and outputs capable of reaching full Low and High levels in 5-V operation (preferably types with rail-to-rail outputs).... [read more]