TREE

With a suitable load, the terminal voltage of a NiCd or lithium-ion battery is proportional to the amount of stored energy. This relationship, which is linear over a wide range, can be used to build a simple battery capacity meter. Circuit Image :   Voltage Tester for Model Batteries Circuit Image  This model battery tester has two functions: it provides a load for the battery, and at the same time it measures the terminal voltage. In addition, both functions can be switched on or off via a model remote-control receiver, to avoid draining the battery when it is not necessary to make a measurement. The load network, which consists of a BC517 Darlington transistor (T2) and load resistor R11 (15 Ω /5 W), is readily evident. When the load is active, the base of T1 lies practically at ground level. Consequently, T1 conducts and allows one of the LEDs to be illuminated. Circuit Diagram : Voltage Tester for Model Batteries Circuit Diagram The thoroughly familiar voltmeter circuit, whi...

1960 Model Transformer-less [Barterer Type] Radio - RCA Victor - Schematic Circuit Diagram

This circuit provides aircraft modellers with extremely realistic beacon and marker lights at minimum  outlay. The project ’s Strobe out-put (A) provides four brief pulses repeated periodically for the wing  (white strobe) lights. In addition the Beacon output (B) gives a double pulse to drive a red LED for indicating the aircraft’s active operational status. On the proto-type this is usually a red rotating  beacon known as an Anti-Collision Light (ACL). The circuit is equally useful for road vehicle modellers, who can use it to flash headlights and blue emergency lights.  Lighting Up Model Aircraft Circuit diagram : Lighting Up Model Aircraft Circuit Diagram All signals are generated by a 4060 14-stage binary counter and some minimal output selection logic. Cycle time is determined by the way the internal oscillator is con-figured (resistor and capacitor on pins 9/10) and can be varied within quite broad limits. High-efficiency LEDs are your first choice for the in...