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120VAC Lamp Chaser

This circuit is basically the same as the 10 channel LED sequencer with the addition of solid state relays to control the AC lamps. The relay shown in the diagram is a Radio Shack 3 amp unit (part no. 275-310) that requires 1.2 volts DC to activate. No current spec was given but I assume it needs just a few milliamps to light the internal LED. A 360 ohm resistor is shown which would limit the current to 17 mA using a 9 volt supply.... [read more]

Sound Effects Generator 2

This circuit uses the Holtek HT2884 IC to produce 8 different sound effects.... [read more]

Whistle On - Whistle Off

This is an extension of the CMOS toggle flip flop circuit with the addition of two bandpass filters and condenser microphone so the relay can be toggled by whistling at it. The condender mic used is a PC board mount Radio Shack #270-090C.... [read more]

PIC diode tester

This is a simple use of the PIC 16F84 about a diode tester.... [read more]

8 Watt Audio Power Amplifier Schematic

Here is the schematic for an 8 watt audio power amplifier. This amp can be used as a simple booster, the heart of a more complicated amplifier or used as a guitar amp. It is very small and portable unit and can be powered through 12V battery.... [read more]

Nicad Battery Charger

his simple charger uses a single transistor as a constant current source. The voltage across the pair of 1N4148 diodes biases the base of the BD140 medium power transistor.... [read more]