A handy circuit based on the '4011 quad nor chip, employing two LEDs flashing at approximately 2Hz to show an at-a-glance reading of the device under test.

Although primarily designed for checking 4-cell or 5-cell R/C receiver batteries, two on-board trimpots allow you to adjust for any battery up to a maximum 25 volts. Voltage readout is shown on a 10-digit bargraph display.

This handy gizmo is ideal for checking the output power of your R/C transmitters. Four super-bright LEDs are used in place of the usual analogue meter, allowing for easy viewing of the monitored RF signal. An on-board variable capacitor sets the frequency for 27Mhz, 35MHz or 40Mhx transmitters. Ham Radio operators might wish to experiment with the front-end L/C tank for frequencies other than standard R/C.

An excellent 'must-have' gadget for those who like to tinker with R/C equipment. This device takes all the guesswork out of setting-up your gimbals. 21 LEDs give a readout of dead accurate pulses all the way from 1mS to 2mS, while other modes allow for a myriad other tests, such as auto sweep (perfect for running-in new motors).

Employing 2 x good old NE555 timer chips, each pulsing a fully proportional signal all the way from 0.8 milliseconds up to 1.2 milliseconds -- in effect throwing the servo horn approximately 50-degrees either side of neutral. A handy feature is the on-board pots with centre 'click', used in order to ascertain an accurate 1.5mS pulse signal, making it easy to set the servo horn for dead centre.
For such a simple circuit the repeatable accuracy is pretty much on par with that of a PIC-based unit. A handy dual PPM source for the channel extender.

A slinky little unit employing a PIC16F84A processor and liquid crystal display. Measures inductance from 10-nanohenry up to 100-millhenry and capacitance from 0.1pF to 900nF. Some clever math is performed each time to calculate the unknown external component value. This value is then scaled in engineering units and formatted for display.
The design uses an auto ranging system so that way you do not need to spend time selecting ranges manually. Another neat function is the "Zero Out" switch that will reset the initial inductance / capacitance, making sure that the final readings of the LC Meter are as accurate as possible.